topped tortilla chip (5)
I believe the answer is:
nacho
'topped tortilla chip' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nacho that I've seen before include "Mexican dish" , "part of a snack?" , "Tortilla chip topped with cheese and spices" , "Piece of tortilla served with sauce" , "Mex. corn chip" .)