Vancouver, BC, March 11, 2024 - NexGen Energy Ltd. ("NexGen" or...

Vancouver, BC, March 11, 2024 - NexGen Energy Ltd. ("NexGen" or the "Company") (TSX: NXE) (NYSE: NXE) (ASX: NXG) is pleased to announce the discovery of new intense uranium mineralization on its 100% owned SW2 Property, 3.5 kilometers (km) east of NexGen’s world-class Arrow Deposit (Figure 1). The new mineralized occurrence in RK-24-183 is located on a previously untested conductor segment of Patterson Corridor East (“PCE”). Localized uranium mineralization was intersected for 19.8 meters (m) between 347.7 and 367.5 m, with peaks up to >61,000 counts per second (cps)*. Exploration is predominantly open in all directions including over 1.5 km along strike (Figures 2 and 3).Leigh Curyer, Chief Executive Officer, commented: “Ten years after the discovery of our world-class Arrow deposit, we are thrilled to be sharing this exciting news. This new intercept reflects the high potential of NexGen's extensive land package in the south-western section of the Athabasca Basin, Saskatchewan and is a testament to the strategic and disciplined approach to identifying new Arrow-type zones of mineralization. Drilling activity is being fully dedicated to this new discovery area to advance our understanding of scope and scale of mineralization. This hole which intersected 3.0 m of up to 61,000 cps is significantly better on all metrics than RK-14-21(the Arrow discovery hole) which intersected less than 0.5 m of greater than 9,999 cps.“I would like to take the opportunity to congratulate and acknowledge the fine dedicated work of the NexGen geological team. Our understanding of the markers of mineralization in the region improve with every drill hole and geophysical survey, and the NexGen exploration programs of the past years have been extremely valuable in contributing to this result. Our highly prospective land position in the south-western section of the mighty Athabasca Basin is still in its infancy, and a significant amount of exploration is in front of us to fully define the extent of mineralization at this location and the balance of Rook I / SW2.”Follow up drilling intersected anomalous features including hematite-quartz breccia, strong silicification, dravitic clay fracture fill, redox alteration, and elevated radioactivity similar to early discovery holes at Arrow in 2014 at the upper limits of that system. Kinematics indicate reverse displacement synonymous with the interpreted structural setting. Use of geological spatial relationships observed at Arrow allows for controlled vectoring of additional drill targets across the prospective hydrothermal system which spans over 1.5 km. Results to date indicate potential that extends along strike and down dip.The overall setting is an approximate analog for the structural controls of Arrow. The target area lies within a large gravity low coupled with a series of disjointed conductive responses. An interpreted regional, north-south cleavage plane bisects the gravity low. A cleavage plane is also interpreted to connect Arrow, South Arrow, and Camp East. Sinistral, strike-slip displacement via contractional jog was hypothesized to account for the geophysical characteristics. This movement sense compares favourably with the sinistral, strike-slip reactivation noted as a key contributor to deposit formation at Arrow.