Melt butter in a saute pan over medium heat. Season peppers, onion, and garlic with 1 teaspoon of salt and saute until they are tender. Add to the slow cooker.
Place chicken breasts in the slow cooker on top of the vegetables. Then add chicken broth, enchilada sauce, cumin, chili powder, oregano, taco seasoning, and remaining 1 tsp salt.
Cook on high for 3-4 hours or until the chicken reaches an internal temperature of 165°.
Remove cooked chicken and shred or chop, then place back into the soup. At this point, add any of the optional ingredients that you wish to use such as corn or beans.
If you'd like a creamier soup, add 1-2 cups of heavy cream now. For a thicker soup, whisk 2-3 tablespoons of flour or cornstarch to the heavy cream before stiring into the soup. Cook on high for another 1 hour.
Serve with your choice of ganishes such as fresh chopped cilantro, sour cream, and tortilla strips. Enjoy!