Vegetarian Tortilla Bake

We have decided to try and limit the amount of meat we consume every week {mostly red meats}. So I've been on the hunt for yummy vegetarian dishes to rotate through and this one is a gold mine!!!!! I made it one day and tested it out on my sisters who fell in love with it and kept requesting it. I love that it makes a LOT and reheats really well! Great to make and eat for lunches throughout the week. Try it and love it!

1 small onion , chopped
1 red pepper , chopped
1 green pepper , chopped
½ teaspoon cumin (or more)
1 teaspoon chili powder (or more)
1 (15 ounce) can chopped tomatoes
1 (15 ounce) can black beans , drained
1 (15 ounce) can canned pinto beans , drained
1 (4 ½ ounce) can mild green chilies , drained
1 (12 -16 ounce) jar salsa
12 wheat flour tortillas (8 to 10-inch)
1 (8 ounce) bag shredded Mexican blend cheese
1 (8 ounce) bag shredded reduced-fat cheddar cheese
light sour cream (optional)
fresh cilantro (optional)

Preheat oven to 350 degrees. Spray a large skillet with nonstick spray; saute onions and peppers over medium-high heat.When the vegetables are tender, add the cumin, chili powder and the can of chopped tomatoes; simmer in the skillet for 5-10 minutes.
In a large bowl, mix together black beans, pinto beans and chiles; mix in jar of salsa. Spray the bottom two 9"x13" baking dishes with cooking spray (a full recipe fills two pans){I just used a large lasagna pan which is a 15x11 pan I think for the whole recipe} Place two tortillas on the bottom of each dish. Spread one-sixth of the vegetable mixture onto the tortillas, then one-sixth of the bean mixture; then sprinkle one-sixth of the cheese on top. Repeat layering two more times in each pan, finishing with the cheese. Cover with foil and bake for 25 minutes; uncover and bake an additional 10 minutes. Remove from oven and let stand five minutes before cutting and serving.
optional: Serve with fresh cilantro and a dollop of light sour cream