This is my very favorite BBQ recipe! You can use chicken breasts if you prefer.
1 c ketchup
1 can Diet Coke
1 onion, diced
1 boneless pork tenderloin
Mix all ingredients except tenderloin. Place tenderloin in bottom of crock pot and pour mixture over it. Double the mixture if you have an especially large tenderloin; the tenderloin should be nearly covered or completely submerged. Cook on low for 8 hours. Shred with a fork.