The Collaborative International Dictionary of English v.0.48:
nacho \nacho\ n. A tortilla chip topped with cheese and often chili-pepper or beans and then broiled; -- eaten as a snack or light meal. [WordNet 1.5 +PJC]WordNet (r) 3.0 (2006):
nacho n 1: a tortilla chip topped with cheese and chili-pepper and broiled