Merriam-Webster says:
A: a belief that race is a fundamental determinant of human traits and capacities and that racial differences produce an inherent superiority of a particular race.

B: Behavior or attitudes that reflect and FOSTER this belief : racial discrimination or prejudice

I THINK that it’s possible to use the N word and not actually believe that whites are better than blacks as described in definition A. Somebody could be using this word just to be funny, to shock his audience, to hurt/insult, or just out of ignorance (not understanding how truly hurtful it is).

BUT I don’t think using the N word could ever get past the second definition Because Using that word is a “behavior” that “FOSTERS” belief in definition A.