Cook the Chicken: Begin by cooking the chicken breasts in salted water. Boil for 12–15 minutes or until fully cooked and tender. Once done, remove from water and allow to cool slightly. Utilize two forks or a stand mixer to shred the chicken.
Combine Ingredients: In a large mixing bowl, add the shredded chicken, mayonnaise (or Greek yogurt), celery, red onion, sweet pickle relish, Dijon mustard, and lemon juice.
Season: Add salt and black pepper to taste. Stir well to combine, making sure the chicken is coated evenly with the dressing.
Adjust Consistency: If you prefer a creamier consistency, add an extra tablespoon of mayonnaise or Greek yogurt. Adjust seasoning if needed.
Chill: For the best flavor, cover and refrigerate for at least 1 hour before serving.
Serve and Garnish: Serve cold, garnished with fresh parsley if desired, and enjoy!