Spray slow cooker with non-stick cooking spray. Place chicken breasts in the slow cooker and pour bottle of BBQ sauce on top of them.
Cook on low for about 6-7 hours or high for 3-4 hours.
Shred chicken and set aside.
Set oven at 425 degrees. Split onion rolls in half and lay on a large baking sheet covered in foil.
Put some shredded BBQ chicken on the top of half of the bun. Place 2-3 strips of bacon on top of the chicken and top with a handful of shredded cheese.
Put the baking sheet in the oven and bake for about 2-3 minutes or until cheese is melted.
Place other half of bun on top of the melted cheese and serve.
Notes
Place any leftover bbq chicken in an airtight container and store it in the fridge for 3-4 days. Or you can store it in the freezer for up to 3 months.