Chilaquiles are like the new and improved nachos, except that they're not new at all, and it is physically impossible to improve perfection.

There are regional variations and secret family recipes, but it's basically fried corn tortillas bathed in a green/red spicy sauce until soft and then garnished with queso fresco (fresh cheese).

Salsa or mole (made with chilli peppers) are the simmering sauces of choice, but the green vs red contest really comes down to what's left in the fridge from the night before.

This is Mexican brunch, amigos.

I.e. Hangover heaven.

Some lovers of chilaquiles in central Mexico don't like their tortilla bits all soft from the simmering salsa, so they add the salsa at the last second to keep 'em nice and crispy. Pulled chicken gets added a lot too, just in case your mind wasn't already blown by deliciousness. 

TL;DR: FRIED. SOMETHING ABOUT SAUCE. CHEESE. LEGIT BREAKFAST NACHOS.