Brown ground beef with onion in 4-quart stockpot; drain, if desired.
Stir in remaining ingredients. Bring to a boil over high heat. Reduce heat to low and simmer covered, stirring occasionally, 7 minutes or until rice is tender.
Garnish, if desired, with sour cream, shredded cheddar cheese and/or sliced green onions.
TIP: Spice it up with hot pepper sauce and/or chopped jalapeno peppers!