Nigger Genius - A direct contradiction it terms
To Be A Nigger = Not a Genius
To Be A Genius = Not a Nigger
However as a slang term "Nigger Genius" is a term meaning
NOT acting smart or intelligently.
Joe: Did you see the news about the Pro Basketball player who was arrested for drugs and wife beating?
Max: Yea, ... he sure is a "Nigger Genius"