In a large mixing bowl, combine the shredded chicken, pesto, Greek yogurt, and mayonnaise. Mix well until the chicken is evenly coated.
Add in the cherry tomatoes, cucumber, red onion, and walnuts. Gently fold the ingredients together, ensuring even distribution without mashing the tomatoes or cucumber.
Season the salad with salt and pepper to taste. Adjust according to your preference.
Cover the bowl and refrigerate for at least 30 minutes to allow flavors to meld. This will enhance the creaminess and depth of taste.
When ready to serve, give the salad a good mix again, then transfer to a serving platter or individual bowls.
Garnish with fresh basil leaves for an extra burst of flavor and color.