The story of Big Fat Nick

So, before I start this story I should mention that I am not from an English speaking country.
Anyway, when I was a kid I was in this youth club. I keep comparing it with scouts cause everyone knows what that is, but instead of learning things we'd just play games and do challenges, usually with a theme. On this one particular day, the theme was native Americans.
We started the day by giving everyone nicknames. The two leaders, Xander and Nick, had chosen names for themselves, "dansende Xander" (dancing Xander) cause he was kinda silly, and "Big Nick" (in English caused it rhymed that way) cause he was a big guy.

So we were a bunch of 8 year olds and only knew a few English words from subtitled cartoons, enough to know 'big' but we thought he was calling himself tall. So one of the smartass kids wanted to make fun of him and said
"Big Nick? More like 'Dik' Nick!",
'dik' being our word for fat (so like thick but it's more of a negative word). Us 8 year olds thought calling him fat was hilarious, so one of us responds with "Yeah! Big Dik Nick!". For the rest of the day, this leader had a bunch of 8 year olds with little English skill call him "big dik Nick", we wondered why he let us get away with calling him fat all day.

I just remembered that again recently and cringed at myself, I imagine this guy has not forgotten.