#she has a couple aliases but stellaluna's closest to a nickname

[vexic929]

Souriya (Spider) and Quinn (Aces) + have nicknames that aren't actually based on their given names

ooh I was thinking about this one for a minute and I thought I didn't have anyone but then I remembered that Aria's "business" name for her more shady dealings where she doesn't want people to know her is StellaLuna so I think that counts (I guess it's kinda close since her name is Lunaria but eh lol)