In a large slow cooker, add the onion, bell pepper, carrots, celery, sweet potato, garlic, chicken, crushed tomatoes, green chiles, chili powder, cumin, cayenne (if using), salt, and broth.
Cook on low for 6-8 hours or high for 4 hours.
Once cooked, remove the chicken and shred.
With the chicken still out of the slow cooker, puree the soup. I use a hand immersion blender to puree the soup directly in the slow cooker. Alternately, you can transfer the soup to a blender and puree.
Return the chicken to the slow cooker along with the beans.
Ladle into bowls and serve with fresh cilantro, diced avocado, sour cream/Greek yogurt, and tortilla chips/strips.