bean & vegetable enchilada casserole

I am on a quest to find recipes that are healthy, inexpensive, and easy. Usually a recipe is 2 of those but not all 3....healthy and inexpensive but hard, inexpensive and easy but processed and unhealthy, etc. Here is a recipe that fits the bill perfectly:

1 med. bell pepper, chopped
1 lg. onion, chopped
2 cloves garlic, minced
1 T. oil
1 can black beans
1 can pinto beans
2 c. frozen corn, thawed (I don't thaw mine, I just throw it in)
1 can (28 oz.) pureed/crushed tomatoes
1 T. chili powder
1/2 t. cumin
dash of hot sauce (I omit)
salt and pepper, to taste
12 corn tortillas (I use four 10-in. whole wheat flour ones)
1 c. grated Jack cheese (I use whatever cheese I have)

1. Preheat 350. In lg. saucepan, heat oil and saute pepper, garlic and onion for 5 mins. Add beans, corn, tomatoes, and seasonings. Reduce heat and simmer for 15 mins.
2. Assemble in 9x13 dish as follows: 1/3 bean mixture, tortillas to cover (2 10-in. work for me), 1/3 bean mixture, tortillas, 1/3 bean mixture, cheese.
3. Bake 30-40 mins. or until hot and bubbly.