Cut the tops off of the peppers. Remove core, seeds, and white membrane.
In a large bowl, combine the beef, salt, pepper, oregano, Italian seasoning, and onion. In a large skillet over medium heat, brown the beef mixture. Drain.
Return the beef mixture to the skillet. Add the chili powder and tomato soup. Cook over medium-low heat for an additional 10 minutes. Stir in the cheese and rice.
Spoon the beef mixture into the peppers. Stand the peppers up in a large baking dish and bake for approximately 30 minutes at 400 degrees.