In a large mixing bowl, combine the cooked chicken, dried cranberries, chopped celery, and finely chopped red onion. Stir gently until evenly distributed.

In a separate small bowl, whisk together the mayonnaise, Dijon mustard, and lemon juice until smooth. Add salt and pepper to taste.

Drizzle the dressing over the chicken mixture and gently toss everything together until evenly coated.

If desired, fold in the chopped walnuts or pecans and chopped parsley gently to combine.

Taste and adjust seasoning with additional salt and pepper if needed. Mix again.

Cover and refrigerate the salad for at least 30 minutes to allow flavors to meld.

After chilling, give the salad a gentle stir and serve on its own, over greens, or in a sandwich or wrap.