NexGen Significantly Extends Mineralization in the A2 and A3 Shears to the Northeast

NexGen Significantly Extends Mineralization in the A2 and A3 Shears

to the Northeast

Vancouver, BC, February 23, 2017 – NexGen Energy Lt d. (“NexGen” or the “Company”) (TSX:NXE,

OTCQX:NXGEF) is pleased to report the first results from the 35 ,000 m winter 2017 drilling program at our

100% owned, Rook I property, Athabasca Basin, Saskatchewan.

Several drill holes have intersected significant mineralization in previously untested areas located outside the

maiden A2 and A3 resource grade shells of the Arrow Deposit to the northeast, including some of the mo st

intense mineralization encountered in the A3 shear to date.

Highlights:

A2 Shear Northeast Extension

• Drill hole AR-17-119c1 has extended mineralization 120 m to the northeast of the maiden A2

resource grade shell intersecting 21.5 m of total composite mineralization including 1.15 m of total

off-scale radioactivity (>10,000 to 53,000 cps) within a 95.0 m section (485.0 to 580.0 m).

• Scissor hole AR-17-116c2 drilled 35 m northeast from the edge of the maiden A2 grade shell

intersected 47.0 m of total composite mineralization including 3.05 m of total off-scale

radioactivity (>10,000 to >61,000 cps) within a 111.0 m section (642.0 to 753.0 m).

A3 Shear Northeast Extension

• Scissor hole AR-17-116c1 was drilled up-dip and northeast in a previously u ntested area

approximately 45 m to the northeast boundary of the maiden A3 resource grade shell intersecting

64.0 m of total composite mineralization including 6.5 m of total off-scale radioactivity (>10,000 to

>61,000 cps) within an 84.5 m section (425.5 to 510.0 m).

• Scissor hole AR-17-114c2 intersected 54.0 m of total composite mineralization including 6.55 m of

total off-scale radioactivity (>10,000 to >61,000 cps) within a 139.0 m section (437.5 to 576.5 m).

• Scissor hole AR-17-118c1 intersected 55.0 m of total composite mineralization including 6.55 m of

total composite off-scale radioactivity (>10,000 to >61,000 cps) within a 104.0 m section (571.5 to

675.5 m).

A2 High Grade Domain

• Scissor hole AR-17-117c1 (25 m southwest and up-dip from AR-15-44b) interse cted 72.0 m of total

composite mineralization including 11.05 m of total composite off-scale radioactivity (>10,000 to

>61,000 cps) within a 151.5 m section (461.0 to 612.5 m).

• Scissor hole AR-17-114c2 (115 m northeast and down-dip from AR-15-44b) inte rsected 41.0 m of

total composite mineralization including 7.35 m of total composite off-scale radioactivity (>10,000

to >61,000 cps) within a 109.0 m section (626.0 to 735.0 m).

• Scissor hole AR-17-114c1 (87 m northeast and down-dip from AR-15-44b) inter sected 77.0 m of

total composite mineralization including 5.7 m of total composite off-scale radioactivity (>10,000

to >61,000 cps) within a 105.5 m section (607.5 to 713.0 m).

Arrow, Activities & Financial

• The 2017 winter program comprising a minimum of 35, 000 m of drilling with seven drill rigs is

underway.

• An updated NI 43-101 resource estimate on the Arrow Deposit is scheduled for the first half of 2017.

• The Company has cash on hand of approximately $70 million.

The A2 and A3 long sections as well as a map showing drill hole locations are shown in Figures 1 to 3. Table 1

is a summary of the mineralized intervals.

Garrett Ainsworth, Vice-President, Exploration and Development, commented: “The objectives of the 2017

winter drill program are weighted towards expanding the area of mineralization at Arrow and subsequent

infilling of the deposit. The first batch of results from the 2017 program have materially expanded the A2 and

A3 shears to the northeast demonstrating continuity of these broad mineralized shears and include high

grade sub-intervals. High grade sub-intervals in th e A2 led us to discover the high grade A2 sub-zone. The

northeast extension of the A2, the up-dip northeast extension of the A3 shear, and the southwest gap

between Arrow and the 180 m southwest area are all high priorities given their growth profiles.”

Leigh Curyer, Chief Executive Officer, commented: “ These initial 2017 results suggest the ultimate ext ent of

Arrow is still in the early stages of definition. I t’s quite remarkable considering the maiden Inferre d mineral

resource estimate published in March 2016 ranks Arr ow as the largest undeveloped uranium deposit in

Canada. The updated resource estimate incorporating 2016 drilling at Arrow is on schedule for release in the

coming months. The 2017 program will continue to ag gressively test the boundaries of the known area of

mineralization which, to date, have continually ext ended the boundaries of Arrow.”

Figure 1: A2 Mineralized Long Section

Figure 2: A3 Mineralized Long Section

Figure 3: Arrow Deposit Drill Hole Locations

Table 1: Arrow Deposit Drill Hole Data

Drill Hole

Athabasca

Group -

Basement

Unconformity

Depth (m)

Handheld Scintillometer Results (RS-120)

Hole ID Azimuth Dip

Total

Depth

(m)

From (m) To (m) Width (m) CPS Range

AR-17-114c1 327 -70 849.50 130.00 436.00 452.00 16. 00 <500 - 11500

454.50 456.00 1.50 <500 - 7000

472.00 474.50 2.50 <500 - 12000

482.00 489.00 7.00 <500 - 3500

493.00 494.00 1.00 <500 - 960

502.50 509.50 7.00 <500 - 52000

514.00 517.50 3.50 <500 - >61000

532.50 533.00 0.50 <500 - 510

607.50 608.50 1.00 <500 - 1900

612.00 617.00 5.00 <500 - 3300

623.50 640.00 16.50 <500 - >61000

645.50 678.00 32.50 <500 - 54000

683.00 689.50 6.50 <500 - 5100

692.00 695.50 3.50 <500 - 3700

698.50 699.00 0.50 <500 - 14000

701.50 713.00 11.50 <500 - 9900

735.00 738.00 3.00 <500 - 530

AR-17-114c2 327 -70 823.50 130.00 437.50 438.00 0.5 0 <500 - 870

441.00 443.00 2.00 <500 - 530

453.00 456.50 3.50 <500 - 12000

465.00 465.50 0.50 <500 - 13700

471.50 472.00 0.50 <500 - 24000

480.50 481.00 0.50 <500 - 1800

485.50 486.50 1.00 <500 - 18000

494.00 507.00 13.00 <500 - 33000

510.00 517.50 7.50 <500 - 5500

524.00 524.50 0.50 <500 - 2600

529.00 531.00 2.00 <500 - >61000

534.50 535.50 1.00 <500 - 11000

539.50 557.50 18.00 <500 - >61000

561.00 563.00 2.00 <500 - 760

569.50 570.50 1.00 <500 - 1100

576.00 576.50 0.50 <500 - 570

626.00 628.50 2.50 <500 - 1200

639.00 639.50 0.50 <500 - 560

644.50 646.50 2.00 <500 - 4000

679.00 680.00 1.00 <500 - 2800

684.00 717.50 33.50 <500 - >61000

733.50 735.00 1.50 <500 - 7600

AR-17-115c1 327 -70 714.50 118.40 451.50 452.00 0.5 0 <500 - 1200

459.00 460.00 1.00 <500 - 2200

479.00 486.50 7.50 <500 - 6500

524.50 525.00 0.50 <500 - 2600

533.50 534.00 0.50 <500 - 1200

536.50 537.50 1.00 <500 - 5700

560.00 560.50 0.50 <500 - 510

603.00 613.00 10.00 <500 - 40000

615.50 619.00 3.50 <500 - 2700

660.00 663.50 3.50 <500 - 2700

674.50 675.00 0.50 <500 - 800

AR-17-115c2 327 -70 786.50 118.40 458.50 459.00 0.5 0 <500 - 1750

465.00 465.50 0.50 <500 - 1820

468.50 469.00 0.50 <500 - 1400

495.00 496.00 1.00 <500 - 11000

501.00 501.50 0.50 <500 - 13000

517.00 520.00 3.00 <500 - 3500

534.00 534.50 0.50 <500 - 760

541.50 542.00 0.50 500 - 13000

550.50 551.00 0.50 <500 - 18000

572.50 573.00 0.50 <500 - 700

580.50 582.50 2.00 <500 - 1670

601.50 602.50 1.00 <500 - 800

608.00 609.50 1.50 <500 - 5200

613.50 621.50 8.00 <500 - 56000

624.00 628.00 4.00 <500 - 22500

632.50 633.00 0.50 <500 - 710

635.50 640.00 4.50 <500 - 8200

644.00 644.50 0.50 <500 - 4300

649.50 655.50 6.00 <500 - 12500

672.50 673.00 0.50 <500 - 740

675.50 676.50 1.00 <500 - 5200

698.50 700.50 2.00 <500 - 2200

AR-17-116c1 327 -70 879.50 132.00 425.50 429.00 3.50 <500 - 17000

431.50 442.00 10.50 <500 - 15000

449.00 461.00 12.00 <500 - 19000

465.50 466.00 0.50 700 - 17000

469.00 494.00 25.00 <500 - >61000

497.50 510.00 12.50 <500 - 24000

605.00 607.50 2.50 <500 - 50000

625.00 625.50 0.50 <500 - 1100

636.00 637.50 1.50 <500 - 750

659.00 661.00 2.00 <500 - 1100

705.50 707.00 1.50 <500 - 700

796.50 799.00 2.50 <500 - 950

802.00 805.50 3.50 <500 - 1450

AR-17-116c2 327 -70 897.50 132.00 440.00 440.50 0.5 0 <500 - 2200

444.00 445.50 1.50 <500 - 5300

457.00 459.00 2.00 <500 - 6900

485.00 485.50 0.50 <500 - 510

489.00 493.00 4.00 <500 - 35000

497.50 499.00 1.50 1200 - 53000

518.00 519.00 1.00 <500 - 49000

522.00 526.00 4.00 <500 - 6600

532.00 532.50 0.50 <500 - 530

537.50 540.00 2.50 <500 - 5800

547.50 549.00 1.50 <500 - 1280

566.50 568.50 2.00 <500 - 1700

571.50 572.00 0.50 <500 - 1150

578.50 580.00 1.50 <500 - 570

642.00 645.50 3.50 <500 - 760

663.50 670.00 6.50 <500 - 6900

673.50 675.00 1.50 <500 - 2300

678.50 682.50 4.00 <500 - 1700

685.00 685.50 0.50 <500 - 860

693.50 710.50 17.00 <500 - >61000

720.50 732.00 11.50 <500 - 41000

734.50 735.50 1.00 <500 - 3700

747.00 747.50 0.50 <500 - 870

752.00 753.00 1.00 <500 - 2100

860.50 861.00 0.50 <500 - 740

AR-17-117c1 327 -70 621.50 124.20 395.00 395.50 0.5 0 <500 - 530

400.00 400.50 0.50 <500 - 1500

407.50 409.00 1.50 <500 - 670

418.00 418.50 0.50 <500 - 900

427.00 427.50 0.50 <500 - 2100

430.00 431.00 1.00 <500 - 600