nitch for me. It just sounds better than neesh. Idk how to describe it, it just flows better in english than neesh which sounds out of place, in my mind 
Edit: People gotta stop bitching about which pronunctiation is "correct" -none are more correct than others. That's the beauty of language, it is ever changing. I love watching languages evolve, even now we see the english language changing all around us within our own countries. It's always nice seeing variations in the same language








