
Preheat oven to 375°F = (190°C)
Butter a 9-by-13-inch casserole dish.
Butter one side of each flour tortilla; set aside.
Brown the ground beef with the onion, and drain any excess grease, if applicable.
Drain the pinto beans, add them to the frying pan with the cooked ground beef and onions. Mash some of the beans to thicken the mixture.
Add the can of green chilies to the frying pan mixture.
Add 2/3 of the green enchilada sauce to the frying pan. Stir until thoroughly combined.
Place one tortilla butter-side down, sprinkle with cheese, and place a small scoop of the meat mixture in the center. Fold in half. Repeat until all 12 flour tortillas are filled and placed in the casserole pan.
Bake for 20-30 minutes until the cheese bubbles and the tops are slightly golden. Do not cover.
Sour Cream (Combine with 1/3 of a can of green enchilada sauce to use as a topping after you bake the tacos). Place a dollop on each taco.