Heat oil in a large Dutch oven over medium-high heat until hot. Add onion and garlic; saute until tender. Add broth and next 7 ingredients. Bring to a boil; reduce heat, and simmer 20 minutes.
Place tortilla strips on a baking sheet coated with cooking spray. Bake at 350° for 10 minutes or until crisp and lightly browned. Set aside to cool.
Stir cilantro into hot broth mixture. To serve, ladle soup into individual bowls, and top evenly with tortilla strips.