I had no idea that Ladybro was a nickname you could set. One of my villagers called me that and didn't ask anything about it, and it doesn't show up in colourful letters (like the other nicknames do). Weird!
I think the nicest one I have is cupcake. The others I find kind of corny, since they're the ones related to the initial letter in your name and those just seem boring to me.
Merengue just came running up to me saying she didn't want to call me "muffin" anymore, so she suggested "cupcake" instead. I'd rather her call me that for sure.