When I read "The Namesake" by Jhumpa Lahiri, I was struck by how the Bengali tradition of having two names (a "nickname" for family and close friends, and a formal name for school and business) was similar to what happens in Guatemalan culture.

Here are some more Guatemalan nicknames that I can think of of the top of my head:

"Gufy" = "Goofy", for a tall, gangly, friendly guy.

"Gamu" = "Bam-Bam" character from the Flintstones (Los Picapiedra). This is the nickname given to a very active and strong little boy.

"El Sauce" = "Willow". This is the nickname given to a really tough guy who was formerly a thief. I think it has to do with the strength of the wood from a willow tree? Some things obviously don't hold up in translation...