547 calories; 29.6 g fat; 4.7 g saturated fat; 50 mg cholesterol; 432.7 mg sodium; 33.3 g carbohydrate; 7.4 g fiber; 2.7 g sugar; 37.5 g protein
Preheat oven to 375°F.
Heat oil in a large skillet over medium heat. Add onion and sauté until translucent, about 5 minutes. Add garlic and cook for 1 more minute.
Add ground beef and cook until browned, about 7 minutes. Drain any excess fat, if necessary.
Stir in taco seasoning, black beans (reserve ¼ cup for topping), tomatoes and corn.
Spray a baking dish with cooking spray and spread ½ cup of the beef mixture on the bottom of the dish.
Top with a layer of tortillas, ⅓ of each cheese, then ⅓ of the beef mixture.
Repeat with another layer of tortillas, cheese and beef.
Top with remaining tortillas and beef mix.
Add remaining cheese and reserved beans.
Bake 20–25 minutes or until cheese is melted and casserole is warmed through.
Garnish with green onions.