4 cups shredded cooked chicken (I use a small rotisserie chicken)
1 tsp vegetable oil
1 small onion, diced
4 oz can roasted green chiles
10 oz can green or red enchilada sauce (I use Casa Fiesta all-natural, from the supermarket)
16 oz can chopped tomatoes
1 Tbsp ground cumin
1 Tbsp chili powder
29 oz can black beans, drained and rinsed
Green (or red) Tabasco, to taste
1/2 tsp kosher salt, or more to taste
2 oat bran tortillas (8-inch burrito size) or other whole grain tortillas
8 oz cheese (I use store-bought low-fat Mexican four-cheese blend)
Shred the chicken and set it aside.
In a large nonstick frying pan, heat the oil over low-medium heat, and sauté the onion until translucent. Add the green chiles, enchilada sauce, chopped tomato, cumin and chili powder. Stir to combine, and cook for 2 minutes. Add the black beans, reserved shredded chicken, green Tabasco (or other hot sauce) and salt. Simmer for 15-20 minutes, stirring occasionally to keep the mixture from sticking, until the liquid is reduced by a third. Remove from heat and set aside to cool for at least 10 minutes (can be made ahead up to this point and refrigerated).
To assemble the casserole, scatter 3 Tbsp of the chicken-bean sauce on the bottom of the casserole. Top with 1 tortilla. Then, spread half of the sauce evenly over the the tortilla, and top it with half of the cheese. Set the second tortilla on top, and follow with the remaining sauce, and then the remaining cheese.
Cover the pan and bake at 375F for 30 minutes. Then, uncover, and bake for an additional 30 minutes, until the cheese is melted and browned.
Serve hot. Can be made ahead and refrigerated or frozen.