Preheat the oven to 375°F (190°C). Cut the tops off the bell peppers and remove the seeds and membranes.

In a skillet over medium heat, cook the ground beef until browned. Drain excess fat.

Add cooked rice, black beans, diced tomatoes, garlic powder, onion powder, cumin, salt, and pepper to the skillet. Stir until well combined and heated through.

Remove from heat and mix in half of the shredded cheese.

Stuff each bell pepper with the beef and rice mixture, pressing down gently to pack it in.

Place the stuffed peppers upright in a baking dish.

Cover the baking dish with foil and bake for 25 minutes.

Remove the foil, sprinkle the remaining cheese on top of the peppers, and bake for an additional 5 minutes, or until the cheese is melted and bubbly.

Remove from the oven and let cool for a few minutes before serving.