Ps some names were changed since I found to cringey so made them worse also my fingers are freezing over feel great full peasent
Tony stark
Yours- sexy, babe and other flirty things like that
His-  idiot (irony at its finest)
Tony wanted to try nicknames and you ended up calling him idiot so whenever he calls you a nickname you call him that

Thor odinson
Yours- poptart
His- cutey

Steve Rogers
Yours- darling
His- capsicle (more silly) since you are a total introvert yo don't really have any romantic nicknames for him

Bruce banner
Yours- sunshine
His- my little genius

Loki
Yours- my queen
His- reindeer games or villain and sometimes you will call him love

Clint barton
Yours- my arrow
His- my bow

Pietro maximof
Yours- princesa
His- swifty or babe

Wanda maximof
Yours- darling
Hers- flower

Natasha Romanoff
Yours- love (rarely calls you that though)
Hers- badass

I hope you liked it I was about to be flirty but then I realised I cant flirt I wanted to say good bye my little and add a name there but all that came up was fanfictionies idk so let's just end there bye bye rose with Frost bite out