Preheat your oven to 375°F (190°C).
Cut the tops off the bell peppers and remove the seeds.
In a large bowl, combine cooked rice, black beans, corn, diced tomatoes, cumin, chili powder, salt, and pepper.
Stuff each bell pepper with the rice mixture, packing it tightly.
Place the stuffed peppers upright in a baking dish.
Sprinkle shredded cheese on top of each pepper.
Cover the dish with foil and bake for 20 minutes.
Remove the foil and bake for an additional 5 minutes until the cheese is bubbly.
Garnish with fresh cilantro before serving.
Enjoy your delicious stuffed bell peppers!