In a bowl, stir together bell peppers, garlic, green onions, chili powder, salt, oregano, cumin, paprika, black beans, and ½ cup cheddar.
Spray a 13x9 baking dish with oil or non-stick spray.
Put about ⅓ cup mixture in a tortilla and roll up. Place filled tortillas seem side down in the prepared baking dish. Fill remaining tortillas and put in baking dish. Add any leftover veggie-bean mixture to the baking dish {I put mine around the sides and in any nooks and crannies that didn't have a tortilla}.
Whisk together milk and eggs, and pour evenly over filled tortillas. Cover with foil and refrigerate overnight or up to 24 hours.
When ready to bake: take enchiladas out of the refrigerator. Preheat oven to 350°F.
Bake casserole for 45 minutes. Uncover, sprinkle with remaining 1 cup cheese, and bake another 10-15 minutes or until cheese is lightly browned & bubbly.
Let sit about 5-10 minutes before serving. Serve with salsa and sliced avocados if desired. Enjoy!