Optional: tortilla chips, low-fat cheese, avocado slices, cilantro for topping
Put everything except for Greek yogurt in your slow cooker and cook on high for 4 hours, or low for 8 hours. You can also make this soup on your stovetop! Simply put everything in a large pot, covered, and cook on medium-low for about 45-60 minutes, or until chicken is cooked through.
If using full chicken breasts, take chicken out of the slow cooker just before serving, and shred. Add chicken back to the slow cooker, and stir in Greek yogurt. Serve warm with your favorite toppings.