I use her with Lilith everytime Assassinate is in the pool. You can throw Lilith at people with Nekima close behind and then when Lilith get's low on wounds get Nekima to kill her to transfer leadership to her and give her melee master (so pretty much 4 AP). That means for the opponent to score VP on assassinate they have to take down a df7 10 wound master with soulstones and then a df5 12 wd monster as well who can also use ss.
But I agree that Nekima is a bit of a glass canon and I certainly wouldn't let her out on her own. She is a beast in melee but she can go down easy which is a lovely waste of 13 points.
The other thing that is awesome is her black blood 0 action with the trigger to do it again. So many times I have got a model down to HTK 1 wd and just needed another 1 damage to kill them off. Just so happens.....
works well with BBS healing her back up.
but defo think she needs handling well by the controlling player and not just throwing at stuff which always seems tempting with her damage output and melee expert