In a large saucepan, heat olive oil over medium heat. Add onion and saute 5 minutes, then add minced garlic and saute another 30 seconds. Add rice, vegetable broth or water, diced tomatoes, salt, pepper, chili powder, cumin, and oregano and bring to a boil. Reduce heat to low and simmer 16-18 minutes or until liquid is absorbed.

Meanwhile, preheat oven to 350 degrees. Slice off the tops of the peppers and scrape out the seeds and membranes. Place peppers snugly in the bottom of an 8 x 8 glass baking dish (or larger, depending on the size of your peppers).

When rice is finished cooking, add corn and beans to the mixture and stir to combine. Spoon carefully into peppers.

Cover tightly with aluminum foil and bake 20 minutes. Remove foil, sprinkle with cheddar, and continue baking another 15 minutes. Serve immediately.