Shredded chicken enchilada casserole

Instructions

1. Preheat oven to 425°F. Coat 13-by-9-inch baking dish with nonstick spray.
2. In large nonstick skillet, heat oil over medium. When oil shimmers, add 2 cups onion and cook, stirring occasionally, until translucent, 2 to 3 minutes. Add mushrooms, zucchini, and 1⁄2 tsp salt and cook, stirring occasionally, until vegetables are softened, 15 to 20 minutes.
3. Meanwhile, make sauce: In blender, purée tomatoes, chipotle pepper (if using), garlic, chili powder, cumin, oregano, and remaining 1 cup onion and 1 tsp salt.
4. Transfer cooked vegetables to medium bowl. Stir in chicken and 1 cup tomato sauce.
5. Spread 1⁄2 cup tomato sauce in bottom of prepared baking dish. Top with 6 tortillas, overlapping to fit dish. Sprinkle with half of chicken mixture and 1⁄2 cup cheese. Top with 6 more tortillas, remaining chicken mixture, and 1⁄2 cup cheese. Top with remaining 6 tortillas. Spread top with remaining sauce and sprinkle with remaining cheese. Bake until golden and bubbling, 15 to 20 minutes.
6. Let cool for 5 to 10 minutes. Serve each piece with 1 tbsp sour cream.
7. Serving size: 1/12 of casserole and 1 tbsp sour cream