Sweet and Sour Slow-Cooker Chicken

I've tried a lot of Chinese take-out inspired meals, but this is the best one by far. I was pretty pleased. :)

3 chicken breasts, cut into bite-size pieces
3 stalks celery, sliced
3 whole carrots, peeled and sliced
1/3 c packed brown sugar
1/3 c Catalina dressing
1/4 c light soy sauce
1 can pineapple chunks (8-10 oz)
1-2 tbsp cornstarch
2 c cooked rice

Place onion, celery, and carrots in slow cooker. Add chicken. In a small bowl, combine brown sugar, Catalina dressing, and soy sauce and pour over chicken. Cover and cook on low 7-8 hours. During the last 30 min of cooking, add the pineapple chunks with the juice. Add cornstarch to thicken sauce. Serve over rice.