Completed and Nicholas is defeated. 4 times :D Doesn't help;)

Exactly! It doesn't help! It's a waste of time - constantly loading saves, going back in the game, trying different development options for Faelan and different tactics - nothing works. Neither phoenixes, nor dwarven artifacts (by the way, their own artifacts are even better), nor the size of the army - nothing saves me :(
And I don't see a way out.
Another interesting point :( - Nicholas has strong allies - Vlad and Deirdre - I fight off Nicholas, but these two are almost stronger and have more troops... It's even frustrating.