Spray crock-pot with cooking spray, place chicken in bottom of pot. Add pineapple tidbits over chicken.
In a small bowl, combine ketchup, orange juice, brown sugar, vinegar, oil parsley, Worcestershire sauce, garlic salt, and pepper; pour over chicken. Cover and cook on low for 5-6 hours.
Remove chicken from a serving platter; keep warm. Skim fat from the cooking juices; transfer 2 cups to a small saucepan. Bring the liquid to a boil.
In a small bowl, combine cornstarch and pineapple juice until smooth. Gradually stir into the pan of cooking juices. Bring to a boil; cook and stir for 2 minutes or until thickened. Serve with chicken.