Heat oil in a saucepan over medium heat then add flour and whisk slowly and constantly for 1 minute. Add seasonings — chili powder through cumin — then whisk until the spices are toasted and fragrant, 30 seconds. Add tomato paste then whisk until combined. Slowly stream in chicken broth while whisking to create a smooth sauce then turn heat up to medium-high to bring sauce to a simmer. Turn heat back down to medium then simmer until sauce has slightly thickened, 3-4 minutes, stirring often. Set aside. Sauce can be made 3-4 days ahead of time.
For the Skillet:
Preheat broiler to high.
Heat oil in a large, 12” oven proof skillet over medium heat. Add peppers and onions then saute until they begin to soften, 5 minutes. Turn heat up to medium-high then add ground beef, chili powder, cumin, garlic, and a pinch of salt. Continue to saute until beef is cooked through and peppers are tender, 8-10 minutes, then drain beef mixture if necessary and add back into the skillet.
Add black beans, frozen corn, and prepared enchilada sauce then stir to combine. Bring mixture to a simmer then add chopped tortillas and fold to combine. Simmer until tortillas are tender, 3-4 minutes, stirring often. Remove skillet from heat then sprinkle shredded cheese on top and broil until melted. Scoop into bowls then serve with optional toppings.
Notes
I recommend using mild chili powder to keep this dish on the mild side. Use spicy chili powder if you’d like it to be spicy.