Season chicken breasts liberally with salt and pepper on both sides. Lay the chicken in a 9-inch x 13-inch baking dish bottom side up.
Spread 2 tablespoons of pesto sauce on each breast and spread it all over the chicken. Flip the chicken over and spread the remaining pesto evenly over each breast.
Bake for 25 min until the chicken is cooked through.
Carefully remove the baking dish from the oven. Lay two slices of tomato on each chicken breast. Top chicken breast with 1/4 cup of mozzarella cheese.
Return the baking dish to the oven and bake for 5 more minutes or until cheese is melty and gooey.
Remove from the oven and sprinkle on fresh basil. Serve with pasta or a green salad. We like to drizzle some balsamic glaze over our chicken before eating.