1. Heat oil in a large nonstick skillet over medium heat. Add onion and next 3 ingredients. Cook 8 minutes or until onion is tender, stirring often.
2. Add seasoning, and cook 1 minute, stirring often. Add beans and tomatoes. Cover, reduce heat, and simmer mixture over medium-low heat 20 minutes.
3. While bean mixture simmers, prepare rice according to package directions, omitting salt and fat. Set aside 4 1/2 cups cooked rice; reserve remaining rice for another use.
4. Serve bean mixture over rice; top with sour cream.