Season the chicken breasts with salt and pepper, to taste. Arrange the breasts on an oiled cookie sheet and bake for 14 to 16 minutes.
Remove the chicken from the oven and cool, then refrigerate for 20 to 30 minutes. Shred or dice the chicken breasts and set aside. Add the mayonnaise, vinegar, celery, pine nuts, ginger and grapes to a medium bowl and whisk well. Fold the chicken into the mayonnaise mixture until well coated. Return the chicken to the refrigerator for 20 to 30 minutes. Transfer to a serving platter and serve with pita chips or use to make a great summer sandwich.