Mix BBQ sauce, brown sugar, cumin, garlic, onion powder and salt and pepper together in the slow cooker.
Add skinless, boneless chicken breast (thighs work great here as well and are less expensive).
Cut the sweet potatoes in half and pierce with a fork several times. Flavor with seasonings of your choice and wrap tightly with foil. Double wrap the potatoes so the sauce doesn't find it's way inside. Place it the crockpot on top of the chicken, close the lid, and cook along with the chicken.
Cook on HIGH for 4-5 or LOW for 7-8 hours or until chicken is fully cooked through.
If cooking on high for 4-5 hours, cut up sweet potatoes in quarters or they might not be done if just cut in half. Timing will vary on cooking depending upon the thickness of your chicken and your particular slow cooker. No need to add water to this recipe. Substitutions: chicken thighs for the breasts work great. Frozen chicken works great in place of fresh. Leftovers are kept safe in the refrigerator for up to 3 days.