A prevalent occurence in the African American community of becoming drowsy after eating a big meal. This generally ends in the person wanting to take a nap. The acronym is derived from "Nigga Eat Nigga Sleep". Synonyms include "niggeritis" and it's shorter form, "itis".
Aight, that meal was good but now I gots the nens. Nothing does a brotha in like good-ol' itis.