– 6 cups cooked chicken,  chopped – 1 cup pecans, coarsely chopped (optional) – 1 cup seedless grapes, halved – 1 Granny Smith apple, cored and diced – 2 stalks celery, chopped – 1 cup mayonnaise – 2 tablespoons dijon mustard – 1 lemon, juice only – ¼ teaspoon celery salt – ¼ teaspoon onion powder – salt and pepper to taste