Wash chicken and pat try. Marinate with Kraft Tuscan House Italian Dressing & Marinade in a large glass dish in the refrigerator for 3-4 hours. You want to use just enough marinade to cover the chicken, about 1/4 to 1/2 bottle.
Preheat oven to 375 degrees. Remove chicken from marinade and place on a baking sheet. Season generously with salt and pepper on both sides. Bake in oven until cooked, approximately 20-25 minutes depending on thickness of chicken and when juices run clear. Remove chicken from oven and let cool.
In a large bowl, combine chopped celery, halved grapes and chopped parsley.
Add 3/4 cup of mayo (I use Hellmann's Canola Cholesterol-Free Mayo... it has 1/2 the fat of regular mayo but better flavor than low-fat or no-fat), 2 tablespoons Kraft Tuscan House Italian Dressing & Marinade, and juice from 1/2 lemon.