Whatever we do with this specific case, we’re still going to have stuff like this, in which a specific artist choose to use “banned” words for/about himself:
Or things like this, which is specifically meant to offend:
Or albums where the cover is literally a dick pick (linking without cover for SFW purposes, in case someone might get fired for looking at genitalia while surfing or something ).
Or, you know, actual nazis, since we can’t stop them from existing and making music, apparently
As such, I wouldn’t worry too much about it, as long as the nickname is not a slur directed at the person to downgrade them. I think it’s certainly reasonable, in this case, to add it as an alias, and if you feel it’s a useful disambiguation help, then there too.
In a case where the nickname was not used by the artist but against the artist, even if actually used about the artist, I would be more likely to skip it.