Preheat the oven to 350°F. Coat a 9x13 baking dish with cooking spray/butter/ghee.
Heat the oil in a large pan over medium heat. Add the ground beef, turkey and onion and cook for 6-8 minutes, breaking up the meat with a spoon.
Mix all the ingredients in the Taco Seasoning together in a small bowl. Add the taco seasoning, diced tomatoes and beans; stir to combine.
Spread 1/4 cup of the enchilada sauce over the bottom of each baking dish you are using to prevent the tortillas from sticking.
Layer 1/2 of the tortillas over the sauce. (dividing this 1/2 into each pan if using 2)
Add 1/2 of the meat mixture spread over however many pans you are using, then add 3/4 cup of cheese on top of the meat to each pan you are using.
Pour 1/2 cup of the enchilada sauce over the cheese into each pan you are using.
Repeat the process with 1/2 of the tortillas, the rest of the meat mixture, 3/4 cup of cheese and 1/2 cup of sauce.
Cover the casserole with foil and bake for 30 minutes. Uncover and bake for an additional 5-10 minutes or until cheese is melted and browned.
Sprinkle green onions over the top. Let the casserole sit for 5 minutes before cutting.