Possible Clues:

• It's extra at Chipotle
• Super Bowl bowlful, familiarly
• Choice at Chipotle, briefly
• Tex-Mex topping
• Nacho topper, for short
• Tex-Mex dip, for short
• Taco stand add-on, in brief
• Tortilla chip topper, informally
• Burrito side, informally
• Nacho dip, for short