Can you call someone "guapo" as a nickname/petname? plus, list any other petnames of that idea.
I think so, yes. i know a few guys in Puerto Rico with this nick name. Also "chulo". Mine in puerto rico was Muneco or Moreno. I think its like english, you can call anyone something that has some significance for you. I had a friend whose nickname was PITUFO! lol SMURF.
A nickname or a pet name can really be anything. It doesn't really have to make sense or even correctly reflect a personal characteristic. The idea is the same in Spanish as it is in English.
So, to answer your question, yes, "guapo" can be a nickname or a pet name.
WE need to know if you wish to apply this to men or women. There are lots of endearing terms.