Quesadilla Casserole

1 lb ground beef
1/2 cup chopped onion
1 can (15 oz) tomato sauce
1 can (15 oz) black beans, drained and rinsed
1 can (14 1/2 oz) whole kernel corn, undrained
1 can (4 oz) chopped green chilies, undrained
6-8 flour tortillas (8 inch)
1 1/2-2 cups shredded cheddar cheese (I use mild)
2 tsp chili powder
1 tsp ground cumin
1 tsp minced garlic
1/2 tsp oregano leaves
1/2 tsp crushed red pepper

1. Brown beef and onion in large skillet on medium-high heat; drain. Add tomato sauce, beans, corn, and green chilies; mix well. Stir in all of the spices except red pepper. Bring to a boil. Reduce heat to low; simmer 5 minutes. Add red pepper to taste, if desired.
2. Spread 1/2 cup of the beef mixture on bottom of 13X9 pan (or 1/4 cup if splitting into 2 8X8's) sprayed with non-stick cooking spray. Top with 3 of the tortillas (or 2 if doing 8X8 pan) overlapping or stacking as needed. Layer with 1/2 of remaining beef mixture, and 1/2 of the cheese. Repeat with remaining tortillas, beef mixture and cheese.
3. Bake in preheated 350 oven 15-20 min (if frozen and thawed 20-30 min) or until heated through. Let stand 5 min before serving.