Begin by shredding your cooked chicken into coarse pieces. You can use leftover rotisserie chicken or poach chicken breasts in advance. Drain the canned corn and chop the olives, green apple, and parsley.
In a large mixing bowl, combine the shredded chicken, yellow corn, chopped olives, raisins, grated carrots, and finely chopped green apple. Toss gently to combine all the ingredients.
Add the mayonnaise to the mixture, starting with 5 tablespoons. Season with salt and freshly ground black pepper to taste. Mix everything until the dressing is evenly distributed.
Lay the lettuce leaves on a serving dish and spoon the chicken salad mixture over the top. Garnish with chopped parsley and arrange the watercress around the edges. Serve with potato sticks or chips for an added crunch.
