Preheat your oven to 425°F and line a baking sheet with parchment paper or place a wire rack over the sheet.
Place the chicken breast between two sheets of plastic wrap and pound to an even half-inch thickness to ensure uniform cooking.
In a shallow bowl, whisk the egg until smooth; in a second shallow bowl, combine the panko, parmesan, oregano, garlic powder, salt, and pepper.
Dip the chicken breast into the egg wash, allowing excess to drip off, then press firmly into the breadcrumb mixture until thoroughly coated on all sides.
Place the coated chicken on the prepared baking sheet, drizzle with olive oil, and bake for 12-15 minutes until the crust is golden and the chicken is cooked through.
Remove from the oven, spoon the marinara sauce over the center of the chicken, and sprinkle with the shredded mozzarella.
Switch the oven to broil and place the chicken back inside for 2-3 minutes until the cheese is melted and bubbling.
While the cheese melts, quickly sauté the zucchini noodles in a non-stick pan over medium heat for 2 minutes until just tender.
Serve the crispy chicken over the warm zucchini noodles and garnish with chopped fresh parsley.