Ne xGe n Update s At-the -Market Equity Program V ancouver, BC, D ecember 11, 2023 - N exGen Energy L td. (“N exGen” or the “Company”) (TS X: NXE)

Ne xGe n Update s At-the -Market Equity Program

V ancouver, BC, D ecember 11, 2023 - N exGen Energy L td. (“N exGen” or the “Company”) (TS X: NXE)

(NYSE: NXE) (ASX: NXG) announced today that it has updat ed its at-the -market equity program (the “ ATM

Program ”) to offer and sell up to C$50 0 million of common shares from treasury (“ Common Shares ”).

Sales of Common Shares, if any, will be made pursuant to the terms of an equity distribution agreement

dated D ecember 11, 2023 (the “ Sal es A greement ”) among t he Company, V irtu I TG Canada Corp., as

Canadian agent, and V irtu Americas, LLC, as U.S. agent (together, the “ Ag e nts”), on the TSX and/or the

NY SE, and/or any other marketplace for the Common Shares in Canada or the United States or as otherwise

agreed bet ween the Agents and the Company. The volume and timing of sales under the ATM Program, if

any, will be determined in the Company’ s sole discretion, and at the market price prevailing at the time of

each sal e, and, as a resul t, sal e pri ces may vary.

The ATM Program is being made pursuant to a prospectus supplement dated D ecember 11, 2023 (the

“Prospectus Supplement ”) to the Company’ s final short form base shelf prospectus filed in all provinces

and terri tori es of Canada dated D ecember 8, 202 3 (the “Base Shelf Prospectus ”), and pursuant to a

prospectus supplement dated D ecember 11, 2023 (the “ U.S. Prospectus Supplement ”) to the Company’ s

U.S. base prospectus (the “ U.S. Base Prospectus ”) included in its registration statement on Form F-10 (the

“Re gistration Statement ”) (File No. 333- 275839) filed with the United States Securities and Exchange

Commission on D ecember 8, 2023 (col l ecti vel y, the Prospectus Suppl ement, Base Shel f Prospectus, U .S.

Prospectus Supplement, the U.S. Base Prospectus and Registration Statement, the “ Offering

Documents ”).

As outlined in the Offering Documents, the Company intends to use the net proceeds from the ATM

Program, if any, to fund the continued development and further exploration of its mineral properties, and

for general corporate purposes.

The ATM Program will be ef fective until the earlier of the sale of all of the Common Shares issuable pur suant

to the A TM Program and January 8, 2026 , unless terminated prior to such date by the Company or the

Ag e nts . Concurrent with the entering into of the Sales Agreement, the Company’ s previously announced

at-the -market equity distribution agreement dated January 6, 2023 was terminated.

Potential investors should read the Offering Documents, Sales Agreement and other documents the

Company has filed for more complete information about the Company and the ATM Program.

About NexGen

N exGen i s a Britis h Colum b ia corporation focus ed on the development of the Rook I Project located in the

southwestern A thabasca Ba s in, Sas katchewan, Canada, into production.

Contact I nformation

L eigh Curyer

Chi ef Executi ve Offi cer

NexGen Energy Ltd.

+1 604 428 4112

lcuryer@nxe -energy. ca

Travis McPherson

Chie f Comme rcial Office r

NexGen Energy Ltd.

+1 604 428 4112

tmcpherson@nxe -energy.ca

M onica K ras

V ice President, Corporate Development

NexGen Energy Ltd.

+44 (0) 7307 191933

mkras@nxe -energy.ca

Copies of Offering Documents

T he Prospectus Suppl ement, the Base Shel f Prospectus and the Sal es A greement are avai l abl e at

www.sedarplus.c a and the U.S. Prospectus Supplement, the U.S. Base Prospectus and the Registration

Statement are avai l abl e at www.sec.gov . Alternatively, the Agents will send copies of the Prospectus

Suppl ement and the Base Shel f Prospectus or the U .S. Prospectus Suppl ement and the U .S. Base

Prospectus, as applicable, upon request by contacting:

Vir tu Am e r ic a s LLC

Attn Capital Markets

1633 Broadway | New Y ork, NY 10019

ATM@V irtu.Com

V irtu I TG Canada

Attn Capi tal M arkets

222 Bay Street | Suite 1720 | Toronto, ON M5K 1B7

ATMCanada@V irtu.com

No securities regulatory authority has either approved or disapproved of the contents of this press

release. This press release is for information purposes only and does not constitute an offer to sell

or the solicitation of an offer to buy the Common Shares, nor shall there be any sale of these

securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior

to registration or qualification under the securities laws of any such state or jurisdiction.

Forward -L ooking I nformation

The information contained herein contains “forward -looking statements” within the meaning of applicable

United States  s e c uritie s laws a nd re gula tions a nd “forwa rd-looking information” within the meaning of

a p plic a ble Ca na dia n s e c uritie s le gis la tion. “Forwa rd-looking information” includes, but is not limited to,

statements wi th respect to mi neral reserve and mi neral resour ce estimates, the 2021 Arrow Deposit, Rook

I Project and estimates of uranium production, grade and long -term average uranium prices, anticipated

effects of completed drill results on the Rook I Project, planned work programs, completion of further site

investigations and engineering work to support basic engineering of the Project and expected outcomes.

Generally, but not always, forward -looking inf ormation and statements can be identif ied by the use of words

such as “plans”, “expects”, “is expected”, “bud get”, “schedul ed”, “ esti mates” , “f orecasts”, “ i ntends”,

“anticipates”, or “believes” or the negative connotation thereof or variations of such words and phrases or

state that certain actions, events or results “may”, “could”, “would”, “might” or “will be t aken”, “occur” or

“be achieved” or the negative connotation thereof.  Statements rel ati ng to “mi neral resources” are deemed

to be forward -looking information, as they involve the implied assessment that, based on certain estimates

and assumptions, the miner al resources described can be prof itably produced in the f uture.

Forward -looking information and statements are based on the then current expectations, beliefs,

assumptions, estimates and forecasts about NexGen’ s business and the industry and markets in whic h it

operates. Forward -looking information and statements are made based upon numerous assumptions,

including among others, that the mineral reserve and resources estimates and the key assumptions and

parameters on whi ch such esti mates are based are a s set out in this news release and the technical report

for the property, the results of planned exploration activities are as anticipated, the price and market supply

of ura nium, the c os t of pla nne d e xplora tion a c tivitie s , tha t fina nc ing will be a va ila ble if and when needed

and on reasonable terms, that third party contractors, equipment, supplies and governmental and other

approvals required to conduct NexGen’ s planned exploration activities will be available on reasonable terms

and in a timely manner and that general business and economic conditions will not change in a materially

adverse manner. A lthough the assumptions made by the Company in providing f orward- looking information

or making forward -looking statements are considered reasonable by management at the time, there can be

no assurance that such assumptions will prove to be accurate in the future.

Forward -looking information and statements also involve known and unknown risks and uncertainties and

other factors, which may cause actual results, performances and achievements of NexGen to differ

materially from any projections of results, performances and achievements of NexGen expressed or implied

by such forward -looking information or statements, including, among others, the existence of negative

operating cash flow and dependence on third party financing, uncertainty of the availability of additional

financing, the risk that pending assay results will not confirm previously announced preliminary results,

conclusions of economic valuations, the ri s k tha t a c tua l re s ults of e xplora tion a c tivitie s will be diffe re nt tha n

anticipated, the cost of labour, equipment or materials will increase more than expected, that the future

price of uranium will decline or otherwise not rise to an economic level, the appeal of alternate sources of

energy to uranium -produced energy, that the Canadian dollar will strengthen against the U.S. dollar, that

mineral resources and reserves are not as estimated, that actual costs or actual results of reclamation

a c tivitie s a re greater than expected, that changes in project parameters and plans continue to be ref ined

and may result in increased costs, of unexpected variations in mineral resources and reserves, grade or

recovery rates or other risks generally associated with mining, unanticipated delays in obtaining

governmental, regulatory or First Nations approvals, risks related to First Nations title and consultation,

reliance upon key management and other personnel, deficiencies in the Company’ s title to its properties,

uninsurable risks, failure to manage conflicts of interest, failure to obtain or maintain required permits and

lic e nc e s , ris ks re la te d to c ha nge s in la ws , re gula tions , polic y a nd public pe rc e ption, a s we ll a s thos e fa c tors

or other risks as more fully described in NexGen’ s Annual I nformation Form dated   February 24, 2023 filed

with the securities commissions of all of the provinces of  Canada  except  Quebec  and in NexGen’ s 40- F file d

with the United States Securities and Exchange Commission, which are available on S EDAR+

at www.sedarplus.ca and Edgar at  www.sec.gov .

Although the Company has attempted to identify important factors that could cause actual results to differ

materially from those contained in the forward -looking information or statements or implied by forw ard -

looking information or statements, there may be other factors that cause results not to be as anticipated,

estimated or intended.    Readers are cautioned not to place undue reliance on forward -looking information

or statements due to the inherent uncertainty thereof.

There can be no assurance that forward -looking information and statements will prove to be accurate, as

actual resul ts and f uture events could dif f er materially f rom those anticipated, estimated or intended.

Accordingly, readers should not place undue reliance on forward -looking statements or information. The

Company undertakes no obligation to update or reissue forward -looking information as a result of new

informa tion or e ve nts e xc e pt a s re q uire d by a p plic a ble s e c uritie s la ws.