Preheat the oven to 350°F.
Cut each piece of chicken in half lengthwise to form 4 thin slices. Flatten the chicken to under half an inch using a meat mallet or rolling pin by firmly hitting it with the rolling pin/mallet. This will both tenderize and make the chicken thinner. Covering it with plastic wrap will prevent the chicken from splattering.
Combine bread crumbs, 1/2 cup of parmesan cheese, and fresh herbs on a plate and set aside. In a shallow bowl, whisk water and eggs and set aside. Spread the flour on a third plate and set aside.
Coat the chicken in the flour and shake off the excess. Dip in egg mixture and then coat in bread crumbs, making sure the crumbs adhere and the chicken is fully coated. Set aside on a plate. Repeat with all chicken.
Heat olive oil in a cast iron skillet over medium-high heat. Add the chicken slices two at a time and sauté until golden and crispy, about 2 minutes per side. Remove chicken and set aside on a plate.
Let the skillet cool slightly and wipe up excess oil if any. Add 1/2 a cup of tomato sauce to the bottom of the cast iron skillet. Return all four pieces of chicken to the cast iron skillet and arrange them with the least amount of overlap possible.
Cover with remaining tomato sauce and remaining parmesan cheese. Top each piece of chicken with sliced fresh mozzarella cheese and optional shredded mozzarella.
Bake uncovered for 20-30 minutes or until chicken is cooked through and cheese is fully melted and golden. Note: Thinly sliced chicken will cook very quickly and will likely be 90% cooked prior to baking. Serve immediately topped with fresh basil, extra grated parmesan and a side of pasta if desired.