Preheat oven to 350° F. Spray a 9×13 pan with cooking spray and set aside.
Heat a large sauté pan to MEDIUM heat. When hot, add beef and chopped onion. Cook together for 10-12 minutes until brown. Drain any excess fat.
Add mushrooms, bell pepper, beans, tomatoes, green chilies and taco seasoning to pan. Simmer for 5 minutes.
Place half of the tortillas on the bottom of the 9×13 pan (ripping them as needed to create a single layer covering the bottom of the pan). Top tortillas with half of beef mixture. Dollop sour cream on beef mixture and spread using the back of a spoon. Place the rest of the tortillas in a single layer over the sour cream (ripping them as needed). Top with remainder of beef mixture. Sprinkle with cheese. Bake for 25 minutes.
Serve this casserole over mixed greens and top it with fresh tomatoes and guacamole for a fresh and flavorful meal!
Nutrition information per serving: 364 Calories; 116 Calories from fat; 12.9 g Total Fat (6.1 g Saturated Fat; 4.1 g Monounsaturated Fat); 71 mg Cholesterol; 431.4 mg Sodium; 34.5 g Total Carbohydrate; 6.2 g Dietary Fiber; 25.7 g Protein; 3.4 mg Iron; 734.7 mg Potassium; 0.1 mg Thiamin; 0.3 mg Riboflavin; 7.7 mg Niacin (NE); 0.3 mg Vitamin B6; 1.8 mcg Vitamin B12; 4.9 mg Zinc; 17.2 mcg Selenium; 76.9 mg Choline.
This recipe is an excellent source of Dietary Fiber, Protein, Riboflavin, Niacin (NE), Vitamin B12, Zinc, and Selenium. It is a good source of Iron, Potassium, Thiamin, Vitamin B6, and Choline.