Pound chicken breasts to an even ½-inch (1.25 cm) thickness. Season with ½ teaspoon salt and the pepper.
Set up three bowls: flour; beaten eggs; and panko mixed with ½ cup Parmesan, Italian seasoning, and remaining ½ teaspoon salt.
Dredge each cutlet in flour, then egg, then the breadcrumb mixture, pressing firmly to adhere. Rest on a rack 5 minutes.
Heat olive oil in a large oven-safe skillet over medium heat to about 350°F (175°C). Fry cutlets 3–4 minutes per side until deep golden brown.
Preheat oven to 425°F (220°C).
Return cutlets to the skillet, top with marinara sauce (leaving a crust border exposed), mozzarella, and remaining ¼ cup Parmesan.
Bake 10–12 minutes, until cheese is melted and bubbling and chicken reaches 165°F (74°C) internal.
Rest 5 minutes, garnish with basil, and serve.