Preheat oven to 350 degrees. Cut the peppers in half lengthwise and remove seeds and ribs. Coat peppers with cooking spray (Pam) inside and out. Place into a baking dish that has been sprayed with Pam as well. Set aside.
In a large saute pan, over medium heat, cook the onion in 1-2 tablespoons of oil until soft. Add garlic, reduce the heat to low and continue to cook 3-5 minutes.
Increase heat to medium and add ground beef. Cook until there is no longer any pink in beef. Stir in taco seasoning, salt, pepper, cumin, brown rice, diced tomatoes, corn, Ortega green chilies, beans, sour cream, and cilantro.
Fill peppers with filling. Bake about 45-50 minutes or until the peppers are soft. Remove from oven and top peppers with cheddar. Return to oven and cook until cheese is nicely melted.