Place the chicken breasts in the bottom of the crockpot.
Add the drained pineapple chunks, diced onion, and minced garlic on top of the chicken.
Pour the barbecue sauce over all the ingredients.
Cover and cook on low for 6-7 hours or on high for 3-4 hours until the chicken is fully cooked and tender.
Shred the chicken in the crockpot using two forks and stir to combine.
Serve hot over cooked white rice.