In a large bowl, combine the shredded chicken, diced celery, and red onion.
In a small bowl, whisk together the Greek yogurt, lemon juice, Dijon mustard, salt, and pepper until smooth.
Pour the dressing over the chicken mixture and toss until everything is evenly coated.
Gently fold in the fresh parsley, dill, and chives.
Taste and adjust seasoning with more salt, pepper, or lemon juice as needed.
Let the salad rest for 10 minutes to allow flavors to meld, or serve immediately.
If using nuts, stir them in just before serving to keep them crunchy.
