[llamabeast]

Oh my goodness, I hadn't even realised there were so many mods!

Anyway, to fix your bug, I suggest disabling some mods.

More specifically, every time you start a game I would just enable the particular mods you want to play with. For example you might decide you want to play an MA game as Skaven, and play against the Tomb Kings, Arga Dis, Ermor and Arcoscephale. In that case just enable Skaven, Tomb Kings and Arga Dis before you start the game. Once you have started the game you are free to select different mods from the "mod preferences" menu for future games. When you continue a saved game it automatically reloads the correct mods for that game.

As for nation number conflicts - certain mod nations will conflict with certain others, but I wouldn't worry about that until you actually hit a problem. Often you can get lucky and not have any problems.