Cook ground beef over medium heat, drain and set aside.
Saute onion and bell pepper in oil until tender. Add to ground beef and mix well.
Stir into the beef mixture the beans, tomatoes, chili powder, salt, pepper,cumin and garlic powder. Mix well.
In crockpot, place two tortillas on bottom, then add 1/4 of beef mixture, then 1/4 of cheese. Repeat this order three more times. Pour enchilada sauce over all, cover and cook on low for 2 1/2 hours. I topped mine with some sour cream, which added to the taste.