Heat 1 tablespoon of neutral vegetable oil in a medium pan. Then grill the chicken breast over low heat, about 6 to 7 minutes per side. Turn off the heat and set aside.
In a bowl, combine together the shredded chicken, olives, corn, grated carrot raisins, apple and corn and stir until the mixture becomes homogenous.
Add the mayonnaise on top of the salad and stir well until everything is evenly coated. Check for seasoning and adjust to your preference with salt and pepper and add the fresh parsley in as well.
Arrange the watercress and lettuce on a platter and scoop the salad in the middle of the platter.
Add the cooked shoestring potatoes on top and chill the salad until it's time to serve.