Place chicken on the bottom of the slow cooker, and then add chopped peppers, onions, celery and parsley. In separate bowl, using a whisk, mix together the vegetable broth, soy, peanut butter, lime juice and cumin.
Add sauce to slow cooker and set on low for 3-4 hours. At around the 3-hour mark, remove the chicken, shred it with a fork and return it to the slow cooker for another 30 to 60 minutes.