Place the chicken breasts inside the crock-pot...OH, and did i mention you can pop the chicken breasts in frozen? I do that all the time! Chop up as much onion as you would like and place the chunks on top of the frozen chicken. I prefer a lot of onion but you can judge the amount to use that you think your family would enjoy.
I pour in enough chicken broth to cover the chicken breasts, I typically do not use the entire can, probably use around two-thirds of it. I also squeeze around two-thirds of the bottle of BBQ sauce into the crock pot as well, covering the chicken. Cook on low for around 6 hours.
When the chicken is done, set the crock-pot to warm and shred the chicken, using 2 forks. The chicken will start to absorb all of the extra liquid and create an amazing, tangy, BBQ sauce.