Prep the Chicken:
Remove the skin and bones from the H-E-B rotisserie chicken. Shred 2 cups of meat into bite-sized pieces.
Mix the Base:
In a large bowl, combine mayonnaise, Dijon mustard, and lemon juice. Whisk together until smooth.
Combine Ingredients:
Add the shredded chicken, celery, and red onion to the dressing. Stir until everything is evenly coated.
Season:
Add salt and pepper to taste. If desired, stir in grapes or pecans for added sweetness and crunch.
Chill:
Cover and refrigerate for at least 30 minutes to allow flavors to blend.
Serve:
Serve chilled on a bed of lettuce, in a sandwich, or with crackers.