In a small skillet, saute onions with the butter over medium-low heat until the onions are nice and golden brown.

In a small saucepan, combine green enchilada sauce with green chilies and heat until very warm.

In the oven (on a baking sheet) or microwave, melt cheese all over the top of each tortilla so that it covers most of the surface area.

To serve, stack three cheesy tortillas on top of one another. Spoon green sauce over the top and add salsa, sour cream, pico de gallo, and cilantro as needed.

Delish and so, so easy!

(Save extra sauce for use on nachos, quesadillas, chicken, etc.)