So Ulo had the key. I guess either Nim's statement was supposed to mean "Ulo is saying the truth and I have the key" or there are two solutions and the dev overlooked one. Or I could be missing something ig
two of them cannot be telling the truth because all three of them say they have the key. there is only one key so Jem is not it. If Ulo is saying the truth, he would have the key, if he is lying, then Nim couldn't have the key. So Nim is lying about having the key if Ulo is telling the truth.