I know a
Carolyn whose nn is
Cal; when she was tiny she called herself Calloryn, which her family found delightful and the nn has stuck into adulthood.
I don't think
Callie ever featured, but it could have, and I can't imagine it as anything other than a nn. There's nothing wrong with that, but it does need something more substantial in reserve.
Kali, the goddess of destruction? Or there's a link to Linux apparently, but I don't know from Linux myself. Either way, it's a definite No.