Preheat your oven to 400°F and line a baking sheet with parchment paper for easy cleanup.
Place the chicken breast between two sheets of plastic wrap and pound to an even half-inch thickness using a meat mallet.
In a shallow bowl, whisk the egg until smooth; in a second shallow bowl, combine the panko, one tablespoon of parmesan, garlic powder, oregano, salt, and pepper.
Dip the chicken into the egg wash to coat, then press it firmly into the panko mixture until the surface is completely covered.
Transfer the breaded chicken to the baking sheet, drizzle with olive oil, and bake for 15 to 18 minutes until the crust is golden and the chicken is cooked through.
Remove from the oven, spoon the marinara sauce over the chicken, and top with the mozzarella and the remaining tablespoon of parmesan.
Set the oven to broil and place the chicken back inside for 2 to 3 minutes until the cheese is melted and bubbling.
While the chicken rests, lightly sauté the zucchini noodles in a pan over medium heat for 2 minutes, then serve the chicken parmesan directly on top.