Start by dicing ¾ cup of celery, finely chopping ¼ cup of red onion, and ¼ cup of fresh parsley. Set aside in a large mixing bowl.

Heat a skillet over low-medium heat, add 1¼ cups of pecans to toast for 3-5 minutes until fragrant and golden. Chop coarsely and set aside.

Fill a pot with salted water to submerge 1.25 lb of chicken breasts, bring to simmer over medium heat. Poach chicken for 12-15 minutes until it reaches 165°F. Shred using two forks.

In a large mixing bowl, whisk together ½ cup of Greek yogurt, ¼ cup of mayonnaise, 2.5 tsp of Dijon mustard, and 1.5 tsp of vinegar. Add salt, garlic powder, and black pepper. Blend until smooth.

In the bowl with the vegetables, add the shredded chicken and toasted pecans. Pour dressing over and gently fold together.

Taste and adjust seasoning as necessary. Serve over mixed greens or in a sandwich. Consider chilling for 30 minutes before serving.