With all-natural ingredients like salsa verde, green chiles, and a creamy homemade sauce, this scrumptious stacked Chicken Enchilada Casserole boasts the great flavor of chicken enchiladas without the work of rolling them!
Adjust rack to center position of oven. Preheat oven to 350°F. Lightly spray a 9- by 13-inch baking dish with cooking spray.
Make the white sauce by melting butter in a medium saucepan over low heat. Add the garlic to the pot and saute until fragrant and light golden brown, about 1 minute. Stir in the flour and whisk continuously for 1 minute. Slowly and gradually whisk in milk and 1/2 cup chicken stock. Increase heat to medium and stir continuously for several minutes until sauce is smooth and thickened. Remove pot from the heat and stir in cumin, garlic powder, and chili powder. Stir in the salsa verde and the sour cream until smooth. Add salt and freshly ground black pepper, to taste.
Evenly scatter half of the shredded chicken in the bottom of the baking dish. Dollop half of the sauce on top of the chicken and use the back of a spoon to spread it in an even layer. Arrange half of the corn tortilla quarters on top, overlapping slightly and tearing in half to fill in any gaps, if necessary. Sprinkle half of the grated cheese on top. Drizzle the entire surface with 1/2 cup of the remaining chicken broth, including corners and edges. Repeat layers of chicken, sauce, tortillas, cheese, and final 1/2 cup broth. Evenly sprinkle diced green chiles over the top of the casserole.
Cover with foil and bake for 15 minutes. Remove foil and bake for an additional 30 minutes, until hot and bubbly.
You may use leftover chicken or cook it fresh by poaching, baking, grilling, cooking in the slow cooker, etc. I typically cook 4 (medium-sized) frozen chicken breasts for this recipe. Alternatively, a rotisserie chicken torn into chunks yields about 4 cups.
For extra kick, you may use Pepper Jack cheese in lieu of the Monterrey Jack.