Preheat the oven to 425 degrees Fahrenheit. Spray a large baking dish or sheet pan with nonstick cooking spray. Split each chicken breast across but not through and open like a book (be careful, you can easily cut yourself doing this!). This is also known as butterflying. On one side of the chicken, lay out 7-8 thin apple slices followed by 4-5 slices of cheese. Sprinkle with 1/2 teaspoon fresh thyme. Fold over and drizzle with 1/2 teaspoon olive oil. Sprinkle with 1/4 teaspoon salt and 1/4 teaspoon pepper. Place the chicken breast on sheet pan and top with another sprig of fresh thyme if desired. In a bowl, mix diced sweet potatoes with olive oil, smoked paprika, 1 teaspoon thyme leaves and sea salt until evenly coated. Arrange sweet potatoes in a single layer around chicken breasts. Bake for 20 minutes and then stir sweet potatoes. Continue to bake until the juices run clear from chicken and internal temperature of chicken registers at 165 degrees, about 10 additional minutes. Sweet potatoes should be fork tender.