Nicknames should be organic...I've been called all sorts over the years, Loopy Lu, juicy lucy, Cindy, Willers, all gifted by friends😂 I choose to just go by a very shortened version now, and many people don't even know my full name
If she was my friend I'd probably call her Carlotta, like I call my friend Emily, Emzels, my pal Karen, Kazarella, my Saturday girl Amber, Ambies etc
She won't be able to force them to use a name of her choosing but she could encourage them to make something up for her themselves