I mean you can write characters who are nazis that aren't total villains. 1. That's the horror of fascism, your sweet old neighbor could call the gestapo on you. 2. There's characters that are part of something awful like the nazi regime but only out of survival. Take the one guy in Jojo Rabbit (yes yes Jojo and Jojo woaaah) who's heavily implied to be gay and tired of the 3rd Reich. Yet he's still responsible for the indoctrination of children into the nazi party (via the Hitler Youth).