Spray a large skillet (at least 12 inch) with non-stick cooking spray and heat the pan over medium heat.
Add the 20-25 broken corn tortillas to cover the bottom of the skillet. Add 2-3 cups cooked chicken and black beans to the pan. Start with about 1 cup black beans and you can add more later if it looks like you want it. Stir together to heat through.
Pour 10 ounces of RoTel, 15 ounces enchilada sauce, and 8 ounces tomato sauce into the pan with ¼ cup cheddar and Monterey Jack cheese. Stir to combine well. Continue to cook 5 minutes, until hot and bubbly.
Sprinkle on the remaining cheese, top with 1 sliced avocado, ½ cup chopped green onions and sliced black olives before serving.
Serve with sour cream, hot sauce and additional cheese on the side.
