Heat oil in large saucepan or Dutch oven over medium-high heat until hot. Add beef; cook 8 to 10 minutes or until beef is well browned. Stir in onions, bell pepper and garlic. Cook 4 to 5 minutes or until vegetables are crisp-tender.
Stir in all remaining chili ingredients. Bring mixture just to a boil. Reduce heat to low; simmer 45 to 55 minutes or until slightly thickened, stirring occasionally.
In small bowl, combine avocado and lime juice. To serve chili, ladle chili into bowls; top with sour cream and chopped avocado.