
Brown the beef in a medium skillet over medium-high heat. Drain off the fat, and transfer to the slow cooker.
Add the remaining soup ingredients, stir together, and cook on low for 6-8 hours (or 3-4 hours on high) until onions and beef are tender.
Ladle into bowls and top with cheese, sour cream, avocado, cilantro, and tortilla chips.