They’re defunct nicknames, and I’m answering this for my fans. 🙂
When I was in Year 8 in high school: Acka Nicka. Because I hit puberty a little early, and acne (Australian slang: ackers) followed soon after.
When I went to a less Lord Of The Flies high school in Year 9: Nick Squared. Because my name and surname are pretty similar.
EDIT: Oh, forgot:
opoudjis is my online name; my PhD was on the distribution of the Modern Greek particle opou, and a Greek lexicographer (who was writing the entry on the word at the time) greeted me once with “Oh! You’re the other opou-guy!” (Είστε ο άλλος οπουτζής!)
More at: opoudjis