Preheat the oven to 350 degrees.

I use two 9 x 13 inch glass baking dishes to build 6 stacked enchiladas, each three layers high. Since one can of enchilada sauce will be used for each baking dish, I make one dish of green chile enchiladas and one dish of red chile enchiladas.

To prepare the filling, chop and onion and soften it in a frypan with a little olive oil. Meanwhile, slice or shred the cooked chicken, then reheat it for a couple of minutes in the microwave.

Now pour a small amount of enchilada sauce in the bottom of each baking dish to keep the tortillas from sticking. Place 3 tortillas flat into each baking dish, spreading them out so they overlap as little as possible.

On top of this, add a layer of cooked onion and chicken, followed by a a layer of shredded cheese, dividing the filling evenly among the 6 tortillas. Only use half of the chicken for now, saving the other half for the next layer.

Next add a layer of tortillas and cover the stacks with enchilada sauce. Begin the second layer with the remaining chicken, and most of the remaining cheese, evenly divided among the 6 tortilla stacks.

Add the final layer of tortillas and cover with the remaining enchilada sauce.

Sprinkle any remaining cheese over the tops of your enchilada stacks. Bake for about 25 minutes, until heated through.