You can respect women or not but it has nothing to do with being a nice guy.
Being the nice guy = not having a spine = not having strong boundaries = not respecting yourself.
Nice guys allow women to behave badly because they fear a woman won't like them if there is conflict. Nice guys try to please people, rather standing on principle and pissing others off. Nice guys want to qualify themselves to women.
You don't have to be a **** to women to be good. You just need to not be afraid of saying what you want to say. Doesn't mean act without a filter, but rather calibrate your interactions.