Preheat the oven to 425°F (220°C). Line a baking sheet with foil and grease it well. Bring a medium pot of lightly salted water to a boil for the pasta.
Prepare three shallow dishes: one for the milk, one for the panko, and one empty plate for the coated chicken. Stir the 1/4 teaspoon salt and 1/4 teaspoon pepper into the panko.
Butterfly the 8-ounce chicken breast by slicing horizontally through the center to create two even, thin cutlets.
Dip each chicken cutlet first in the milk, then press into the seasoned panko to coat both sides. Place the coated cutlets on the prepared baking sheet.
Bake the chicken for about 10 minutes, or until the internal temperature reaches 150°F (65°C).
While the chicken bakes, heat the 1 1/2 cups red sauce in a small saucepan and cook the 4 ounces fettuccine according to package instructions; drain when done.
When the chicken registers 150°F, spoon about 1 heaping tablespoon (approximately 2 tablespoons total) of sauce over each cutlet. Sprinkle the 1/2 cup shredded mozzarella and 1/4 cup shredded Parmesan evenly over the two cutlets.
Return the chicken to the oven and bake an additional 5 minutes, or until the cheese is melted and the chicken reaches 160°F (71°C).
Remove the chicken from the oven and let rest for 5 minutes. Plate the fettuccine, spoon the remaining sauce over the noodles, and place the chicken on top to serve.