Ok, here's a nuke solution for Tame 1 that uses 15 each and believe it or not, loses just 1!
This exploits the fact that oh-noers can still exit successfully, even one that's one frame away from exploding when reached the exit trigger. Calling that out now in case future versions of NeoLemmix changes that behavior. A lemming that is assigned stacker, platformer or fencer will transition to oh-noer when their nuke timer's up, and before that they will also continue carrying out their skill even in mid-air, such as from some other lemming's explosion taking out the ground they are on. When they oh-no, due to being in mid-air they will fall as oh-noers.
So the lemmings that would've exploded early mid-fall gets to fall down as oh-noers instead, which would delay their explosion, and with a short enough fall like on this level, they can reach the exit before their scheduled explosion can occur. Once hitting the exit trigger, the oh-no lemming "forgets" about its pending explosion and will exit successfully.
The main trickiness with realizing this solution is that NeoLemmix doesn't allow multiple (simultaneous) skill assignments to different lemmings on same frame. In order to have enough frames to assign skills to all affected lemmings, you have to start assigning a bit further back from when the first lemming explodes. And it turns out it's not easy to keep a lemming doing stacker, platformer or fencer for that long. In my solution I had to carefully control how the lemmings overlap in position so the stacking doesn't stop prematurely, and also need to use bashers fencers to extend their mid-air stance until they can oh-no. (When you have multiple stackers at exact same position and facing direction, it seems that after the second stack brick has been laid down, the game will inevitably stop all but one stacker.)
There are likely a few more nuke levels where this technique can be used. The key is having a short enough fall to the exit.