Preheat the oven to 400 degrees Fahrenheit.
In a sauce pan, melt the butter on medium heat. Then, saute the peppers and onions for 5 minutes mixing occasionally.
While the peppers and onions cook, mix together in a large bowl the cream of chicken and mushroom soups, Ro*Tel, chili powder, and diced chicken breast. Once the onion and peppers are done cooking mix those in too.
Spray a 2 quart glass baking dish with non-stick cooking spray. Then, layer one-third of the corn tortillas, half of the chicken mixture and 1 cup cheese evenly in dish. Repeat by layering once more. Then add the remaining corn tortillas to the top followed by a thick layer of (1 cup) shredded cheese (make sure the cheese covers all the corn tortilla. Cover with aluminum foil and bake for 25 minutes.
Remove the foil and bake 5 minutes longer. Remove from the oven, cut into 6 slices and top with a dollop of sour cream. Enjoy immediately.