Place chicken breasts between plastic wrap and pound to ½-inch thickness. Season with salt and pepper.
Set up three shallow dishes: flour in the first, eggs + water in the second, and a breadcrumb-Parmesan-spice mixture in the third.
Dredge chicken in flour, dip in egg wash, then coat in breadcrumbs. Press to adhere.
Heat oil in skillet over medium-high. Fry chicken 3–4 minutes per side until golden and cooked through. Drain on paper towels.
Preheat oven to 425°F (220°C). Spread 1 cup marinara sauce in baking dish.
Place chicken in dish. Top with remaining sauce and sprinkle with mozzarella and Parmesan.
Bake for 15–20 minutes until cheese is melted and bubbly. Let rest 5 minutes.
Garnish with fresh basil and serve.