Hi there, and welcome to the forums! Although we have listed on the なさる grammar page that it can be paired with the stem form of う and る verbs, in reality this is actually extremely rare. なさる is almost exclusively used either by itself, or when paired with する verbs.
I will add a note to the なさる grammar description about this. になる on the other hand will often pair with either the stem form of う and る verbs, or する verbs.