01 - In a large mixing bowl, thoroughly combine the diced chicken, chopped pecans, finely sliced celery, halved red grapes, and finely diced red onion.
02 - In a separate small bowl, vigorously whisk together the mayonnaise, plain Greek yogurt, Dijon mustard, fresh lemon juice, salt, and black pepper until the mixture is smooth and well-emulsified.
03 - Carefully pour the prepared dressing over the combined chicken and vegetable mixture. Gently toss all ingredients until they are uniformly coated with the dressing.
04 - If desired, fold in the chopped fresh parsley at this stage to enhance flavor and presentation.
05 - Cover the bowl tightly and refrigerate the chicken salad for a minimum of 30 minutes. This chilling period allows the flavors to meld and deepen.
06 - Serve the chilled chicken salad as desired: on a crisp bed of lettuce, as a sandwich filling, or accompanied by crackers.