- Preheat oven to 350° F and spray a 13x9-inch baking dish with nonstick spray. Set aside.
- For the creamy mushroom sauce: In a medium saucepan, melt the butter over medium-high heat. Add the minced onion and sauté until soft, 2-3 minutes. Add the chopped mushrooms and stir often until they are softened, about 2 minutes. Sprinkle the flour over the onion-mushroom mixture and cook for about 1 minute. Whisk in LACTAID® Milk and stock; let it cook over medium heat for 6-8 minutes, until thickened. Remove from heat and set aside. Season with salt and pepper.
- For the casserole: Wrap the tortillas in damp paper towels and microwave for 15 seconds to soften. Spread 1/3 cup of the mushroom sauce on the bottom of the baking dish. Place 6 tortillas on top, overlapping and coming up the edges of the dish.
- Add 1 cup shredded chicken, 1 cup of the creamy mushroom sauce, 1/2 cup of the green chiles and 1/4 cup of the shredded cheese.
- Repeat the layering 2 more times. Finish with a layer of tortillas. Top with any remaining creamy mushroom sauce and green chiles.
- Bake for 30 minutes. Let cool 10 minutes before slicing and serving.
* Ingredient used in the nutrition analysis ** 3 cups reduced fat shredded cheddar cheese contains approximately 2 grams of lactose. Reference: USDA National Nutrient Database for Standard Reference Release 27