1. Preheat oven to 400°F. Spread tortilla strips on baking sheet sprayed with no stick cooking spray. Bake 8 to 10 minutes or until crisp and golden, stirring after 5 minutes. Set aside.
2. Meanwhile, heat oil in large saucepan on medium heat. Add onion; cook and stir 2 to 3 minutes. Add ancho chile pepper, garlic, cumin and bay leaves; cook and stir 2 to 3 minutes. Add stock and tomatoes. Reduce heat to low; simmer, uncovered, 30 minutes. Discard bay leaves. Thicken soup, if desired.
3. To serve, place a small amount of chicken in each serving bowl. Ladle soup over top. Sprinkle with tortilla strips.
To thicken soup: Allow soup to cool slightly. With center part of cover removed to let steam escape, puree soup in batches in blender on high speed until smooth. Return soup to saucepan and simmer until heated through.
Serving Suggestion: Serve with assorted toppings such as chopped avocado, shredded Monterey Jack cheese and chopped fresh cilantro.