In a mixing bowl, whisk together the barbecue sauce, chicken broth, soy sauce, apple cider vinegar, brown sugar, garlic powder, onion powder, salt, and pepper until well combined.
Place the chicken breasts in the slow cooker. Pour the marinade over the chicken, ensuring they are well coated.
Cover the slow cooker with the lid and set it to cook on low for 6 hours.
After the cooking time is complete, carefully remove the chicken using tongs. It should be tender and easy to pull apart.
If desired, shred the chicken with a fork and return it to the slow cooker, mixing it into the sauce. Alternatively, serve the chicken whole with sauce poured over the top.
Garnish with chopped fresh parsley if desired and serve hot.