Scrub the outside of each potato and remove any blemishes. Poke the outside of each sweet potato multiple times with a fork then place on a baking sheet and place on the middle oven rack.
Heat oven to 425 degrees and bake for 45 minutes, or until a fork easily presses into the center.
Meanwhile, spray a 9 x 13 inch baking dish with nonstick cooking spray.
Place chicken breasts in prepared pan and cover with BBQ sauce.
Bake at 375 degrees for 25-30 minutes, or place in the oven with the sweet potatoes for the last 20 minutes of cooking. Make sure chicken is cooked all the way through.
Remove chicken and sweet potatoes from the oven. Shred cooked BBQ chicken.
Cut each sweet potato down the middle and fill with shredded chicken.
Divide mozzarella cheese, red onion and chopped cilantro evenly between each potato and put on top of each baked potato.
Broil on high for 2-3 minutes, or until cheese is completely melted. Serve hot.