Step 1: Prepare the Beef Mixture

1. In a large skillet, heat a small amount of oil over medium heat.
2. Add the ground beef, breaking it up with a spatula as it cooks. Cook for about 5-6 minutes or until browned.
3. Once the beef is no longer pink, add the diced onion and minced garlic. Cook for 2-3 minutes until the onion becomes translucent and fragrant.
4. Stir in the taco seasoning, chili powder, and cumin powder. Mix well to coat the beef with the spices, adjusting salt and pepper as needed.

Step 2: Add Vegetables and Beans

1. Add the black beans, diced tomatoes with green chiles, and corn to the skillet with the beef mixture.
2. Add the diced red bell pepper, stirring well to combine all ingredients.
3. Let this mixture simmer for about 5 minutes, allowing the flavors to meld together and the sauce to slightly thicken. Remove from heat.

Step 3: Assemble the Bake

1. Preheat the oven to 375°F (190°C).
2. Transfer the beef and bean mixture into a greased 9×13-inch baking dish, spreading it out in an even layer.
3. Sprinkle the shredded cheddar cheese evenly over the beef and bean mixture.

Step 4: Prepare Crispy Tortilla Strips

1. Place the tortilla strips in a mixing bowl and drizzle with olive oil. Toss to coat.
2. Sprinkle with smoked paprika and a little salt for added flavor.
3. Spread the tortilla strips evenly on a baking sheet and bake in the oven for 10-12 minutes until they’re golden and crispy. Keep an eye on them to prevent burning.

Step 5: Bake the Casserole

1. Place the baking dish in the preheated oven.
2. Bake for 15-20 minutes, or until the cheese is melted and bubbly.
3. Carefully remove the casserole from the oven.

Step 6: Add Toppings and Serve

1. Scatter the crispy tortilla strips over the top of the casserole.
2. Garnish with dollops of sour cream and sliced green onions.
3. Serve hot and enjoy!