Optional: Shredded cheddar cheese, sour cream, and green onions
In a large saucepan, cook beef and onion over medium heat until meat is no longer pink; drain. Stir in the remaining ingredients. Bring to a boil. Reduce heat; cover and simmer until flavors are blended, about 30 minutes. Top with shredded cheese, sour cream, and green onions, if desired.