Preheat your oven to 350°F (175°C).
In a large skillet, heat the olive oil over medium heat. Add the diced bell peppers and sauté for 5 minutes until softened.
Add the ground beef (or turkey) to the skillet, breaking it up with a spatula. Cook until browned and cooked through, about 8-10 minutes. Drain excess fat if necessary.
Stir in the cooked rice, black beans, diced tomatoes with green chilies, garlic powder, onion powder, chili powder, cumin, salt, and pepper. Mix well until all ingredients are combined and heated through.
Transfer the mixture into a 9x13-inch baking dish. Spread it evenly.
Sprinkle the shredded cheese over the top of the casserole.
Cover the baking dish with aluminum foil (optional) to prevent excessive browning, and bake in the preheated oven for 25 minutes.
Remove the foil and bake for an additional 15 minutes until the cheese is bubbly and slightly golden.
Remove from the oven and let it cool for a few minutes. Garnish with fresh cilantro or parsley if desired.
Serve warm and enjoy!