Heat oil in a Dutch oven over medium-high heat. Add onion and garlic; saute for 2 minutes. Stir in chicken and next 9 ingredients
(chicken through tomato soup); bring to a biol. Reduce heat and simmer 1 hour.
To Freeze: Ladle soup into family sized portions, into freezer containers.
To Reheat: Reheat from defrosted or frozen, in a covered pot. Ladle into bowls and top with tortilla chips and sour cream.