Begin by shredding your rotisserie chicken into bite-sized pieces.

Dice the celery and red onion, and halve the grapes.

In a small bowl, combine the mayonnaise, Dijon mustard, and lemon juice.

In a large mixing bowl, add the shredded chicken, chopped vegetables, and dressing. Toss gently.

Add salt and pepper to taste.

Fold in the chopped walnuts or pecans if using.

Cover the salad and let it chill in the refrigerator for at least 30 minutes.

Serve the salad on a bed of greens, in a sandwich, or on its own.