1. Coat a nonstick griddle or skillet with cooking spray and place over medium heat.
2. Grill chicken, flipping once, until cooked through, about 5 to 7 minutes per side.
3. Spread half of the panini with mayonnaise.
4. Then top with cheese, apples and chicken.
5. Grill sandwich, flipping once, weighing the sandwich down with a small skillet as it cooks, about 3 minutes total (or cook in a panini press).