I found many candidates in ReVo: alnomo, alinomo, kaŝnomo, kromnomo, karesnomo. I doubt they are all synonyms. In which situations should I use each one?
I'd like to find the one to use when presenting oneself. For example "Hi, my name is Robert, but my nickname is Bob". Or when someone has a really long name, I might want to ask "Do you have a nickname"?