Place the chicken in the bottom of a large slow cookers. Then add the chicken broth, onion, salsa and tomatoes. Next add the beans, corn, cumin, chili powder and salt. Cook on low for 6 to 8 hours or high for 3 to 4. Shred chicken and salt and pepper to taste. Turn off the heat and stir in the sour cream just before serving.
Ladle soup into bowls and add cheese, cilantro and tortilla strips if desired.
Notes
This also makes a great freezer meal. Place the leftover in a freezer safe bag or container and label. Then place in warm water to thaw and reheat on the stove.