Preheat oven to 400ºF (200ºC). Lay tortillas in single layer on baking sheet. Bake, flipping once, for 10 to 12 minutes or until crisp and lightly toasted. Let cool completely.
Meanwhile, in large saucepan, combine 2 cups water, tomato sauce, diced tomatoes, chipotle pepper and chicken bouillon; set over medium-high heat and bring to boil. Reduce heat and simmer for 10 minutes.
Add fideos and mixed vegetables. Cook, stirring often, for about 10 minutes or until noodles are tender. Ladle into soup bowls. Garnish with avocado and cilantro. Serve with toasted tortillas and lime wedges.
Note: Use two chipotle peppers for a spicier soup.