In slow cooker, stir chicken, corn, broth, tomatoes, onion, sugar, ancho powder, garlic and salt.
Cook, covered, on low 6–8 hours, or on high 3–4 hours.
Preheat oven to 350 degrees.
Take two tortillas and cut into ¼-inch-wide strips. On baking sheet, arrange tortilla strips in single layer. Bake 8–10 minutes, or until crisp. Transfer baking sheet to cooling rack. Let strips stand 15 minutes, or until cool. Transfer to airtight container and set aside.
When soup is ready, transfer 1 cup to food processor or blender. Tear remaining tortilla into pieces and stir in. Let mixture stand 1 minute. Process until smooth. Stir mixture into soup. Stir in cilantro. Ladle soup into bowls. Sprinkle with avocado, bell pepper and reserved tortilla strips.