Nilla is a slur used to describe Whites in a derogatory way. Used by white people to describe other white people, is offensive if black people say it to whites. (i.e. "sup mah nilla?") Mocking the fact that its offensive to blacks when whites say nigger. Reference to the coloring of vanilla flavored foods.
The word Nilla is a racial slur that has been used historically to degrade and dehumanize whites. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to whites. If you are unsure about whether or not it is appropriate to use the word Nilla, it is best to err on the side of caution and avoid using it in any situation.