In Argentina if someone is of darker skin, people automatically call him Negro.
This is made out of love and not racism. We have lots of famous people nicknamed "Negro"
El Negro Gonzales Oro
El Negro Ibarra 
For example.

I've met lots of kids in school nicknamed El Negro. They take it and use it no problema.

It has to do with the fact that african descendants were exterminated in wars because they were sent to the front with the promise of freedom. The few people that gained their feeedom and citizenship were really special ones. 

There is a lot like it in our culture.
We nickname very often with things that would be considered offensive in other parts of the world.