My husband,
Kevin, was called
George due to his love of Curious
George. Sure
George isn't the same as Peanut, but it did suit his personality. Our daughter
Cecily is called Bear (or little bear), which does not describe her personality in the least.
I think nns like Pumpkin, Peanut, etc are fine for younger kids- I can even understand parents using them on occasion for older children- but for use outside immediate family and on adults, I would find ridiculous.