01 - Preheat oven to 400°F. Line a baking sheet with parchment paper or lightly grease it.
02 - Place chicken breasts between two sheets of plastic wrap and pound to an even 1/2-inch thickness.
03 - Arrange flour in the first shallow dish. In the second dish, whisk eggs with milk. In the third dish, combine breadcrumbs, Parmesan, garlic powder, oregano, salt, and pepper.
04 - Dredge each chicken breast in flour, shaking off excess. Dip into the egg mixture, then coat with breadcrumb mixture pressing gently to adhere.
05 - Heat olive oil in a large skillet over medium-high heat. Fry chicken breasts 3–4 minutes per side until golden brown. Transfer to prepared baking sheet.
06 - Spoon 2–3 tablespoons marinara sauce over each chicken breast. Top evenly with shredded mozzarella.
07 - Bake in the preheated oven for 15–18 minutes until cheese melts and chicken reaches internal temperature of 165°F.
08 - Bring large pot of salted water to boil. Cook spaghetti until al dente according to package instructions. Drain and toss with olive oil and 1 1/2 cups marinara sauce.
09 - Serve spaghetti topped with a chicken breast. Garnish with fresh basil if desired.