Preheat Oven to 375°F (190°C). Grease a 9x13-inch baking dish.
Sauté the Onion:
Heat oil in a large skillet over medium heat.Add diced onions and cook for 2-3 minutes until soft.
Prepare the Sauce:
Stir in diced tomatoes with green chilies, cream of chicken soup, cream of mushroom soup, chicken broth, chili powder, cumin, and garlic powder.Mix well and let simmer for 2 minutes.
Assemble the Casserole:
Spread a thin layer of the sauce on the bottom of the baking dish.Add a layer of corn tortillas, followed by shredded chicken, more sauce, and cheese.Repeat layers until all ingredients are used, ending with cheese on top.
Bake the Casserole:
Place in the oven and bake for 30 minutes until bubbly and golden.
Let Rest & Serve:
Let the casserole sit for 5 minutes before serving.Enjoy warm with fresh cilantro, jalapeños, or sour cream if desired.
Notes
For extra spice, add chopped jalapeños or a dash of hot sauce.
Use flour tortillas instead of corn for a softer texture.
Make it gluten-free by using gluten-free soups.
Store leftovers in the refrigerator for up to 3 days or freeze for up to 2 months.