Cook the beef, onion and pepper in a 10-inch skillet over medium-high heat until the beef is well browned, stirring often to separate the meat. Pour off any fat.
Stir the broth, tomato sauce, chili powder and garlic powder in the skillet and heat to a boil. Stir in the rice. Reduce the heat to low. Cover and cook for 20 minutes or until the rice is tender. Serve with the cheese and sour cream, if desired.