This is a recipe I found by Rocco Dispirito from his Now Eat This cookbook. It is a favorite of ours. The parmigano reggiano can be expensive cheese and you can actually use less than is called for and it is just as good and still very cheesy. You could also choose to use Parmesan Cheese if you have that on hand. This is great with spaghetti squash. Enjoy.
Preheat the oven to 400 degrees. Lightly spray a 9 x 13 inch glass baking dish with olive oil spray and set aside.
Heat a grill or grill pan over high heat. Season the chicken with salt and pepper to taste. When the grill is hot, spray the chicken lightly with olive oil spray. Grill until just cooked through, about 1 ½ minutes per side.
Spread a little less than half of the marinara sauce over the bottom of the prepared baking dish. Lay the grilled chicken breasts on top of the sauce. Spoon the remaining marinara sauce over the chicken; scatter the chopped tomatoes over the top. Sprinkle with ½ cup of the chopped basil, the mozzarella and the Parmiganio-Reggiano.
Bake the chicken until the cheese has melted and is beginning to brown, 10 to 12 minutes. Sprinkle the panko and the remaining basil on top, and serve.