To reheat in a slow cooker: Place the frozen chili in a slow cooker, add 1/2 cup water or chicken broth in the bottom, and cook on low for 8 hours. To reheat on the stove-top: Defrost the chicken chili in the refrigerator overnight, and reheat in a large heavy-bottom pot on medium-low, about 10 minutes. Make sure to stir the mixture frequently to prevent the bottom of the pan from burning.