Preheat the oven to 350° F.
Heat the olive oil in a large skillet over medium-high heat.
Add the chopped onion and cook for 2 minutes, stirring often.
Incorporate the ground beef and cook until browned, crumbling it as you go. Drain off any excess grease.
Add the chopped red bell pepper to the skillet and cook for 2 more minutes.
Stir in the chili powder, cumin, garlic powder, oregano, salt, pepper, corn, black beans, and 1 cup of salsa.
Remove the skillet from heat.
Spread the remaining salsa evenly in the bottom of a 13x9-inch baking dish.
Lay 4 tortillas in the dish, covering the bottom.
Spread ⅔ of the beef mixture over the tortillas, then sprinkle ⅓ of the shredded cheese on top.
Add the remaining tortillas followed by the rest of the beef mixture and finish with the remaining cheese.
Cover the baking dish with foil and place it into the preheated oven.
Bake for 25 minutes.
Uncover and bake for an additional 5-10 minutes until the casserole is hot and bubbly, and the cheese begins to brown.
Once done, remove from the oven and let it cool for a few minutes.
Serve with your favorite taco toppings like cilantro, avocado, and sour cream for extra flavor.