Here is the link to the actual recipe from Alton Brown’s website, or just follow the instructions below, I have made a couple changes to make the process easier for me. I have removed a couple steps because it again makes it easier for me. The original recipe is really good but I like the shredded chicken it in my eyes makes an improvement on the recipe, but that’s just me.
Alton Brown's Chicken Enchilada Lasagna
Heat the oven to 350 degrees F
Combine the chiles, garlic, chili powder, cumin, chicken broth, tomato sauce, salt and pepper in a medium saucepan and put over high Bring to a boil then reduce the heat to low and simmer for 15 minutes or until the chiles are soft. Set aside until ready to use.
Heat the vegetable oil in a large skillet over medium-high heat. Add the onions to the same pan along with a generous pinch of salt, decrease the heat to medium-low and sweat for 4 to 6 minutes. Add the garlic and oregano and cook until the onions are tender, 2 to 3 minutes more.
While onion is cooking, take the chicken out of the cans, shred with fork, then add it to the onion mixture on the stove top, cook for a minute then take mixture of the heat.
Lube a 13x9" glass baking dish with non-stick spray then dose half a cup of the sauce into the bottom of the dish. (I usually spread it around with a large rubber spatula.)
Dip 4 tortillas (three whole and one cut into halves) into the remaining sauce and lay them into the bottom of the dish. Cut 1 of the tortillas in half to evenly cover the bottom of the dish. (see diagram)
Top this with half of the chicken mixture and 1 cup of the cheese. Repeat layering finishing with the remaining sauce and remaining cup of cheese.
Cover with foil(Spray foil with cooking spray to keep the cheese froms ticking to the top) and bake in the middle of the oven for 30 minutes. Then remove the foil and bake an additional 10 minutes, or until cheese on top is bubbly.