HMMMM i've never actually given this much thought lol. i think peach would probably call mk "sweetheart/sweetie" mostly. mk just calls her peach, princess, and maybe "bella" (spanish for beautiful) in more intimate moments. bayonetta is a canon nickname lover so i'm sure she'd have one for mk, maybe "little bat" or "batsy" something. but she would also call him "love" and "baby" when they're being more serious. mk would just call her bayonetta until they're dating, then he would call her cereza, which is her real name, and just happens to mean cherry in spanish lol so it sounds sweet anyway. in gameverse, daroach would also call mk "love" and maybe "darling". mk would call him "love" back probably. i have a couple other fave ships but that's about all i can think of for nicknames!