Preheat your oven to 400°F and line a baking sheet with parchment paper for easy cleanup.
In a shallow bowl, whisk the egg until smooth. In a separate shallow dish, combine the panko breadcrumbs, parmesan, garlic powder, oregano, sea salt, and black pepper.
Dip the chicken breast into the egg wash, then dredge it through the panko mixture, pressing firmly to ensure an even, crispy coating.
Place the chicken on the prepared baking sheet and bake for 15-18 minutes until the internal temperature reaches 165°F.
Remove from the oven, spoon the marinara sauce over the chicken, and top with the mozzarella cheese. Broil for 2-3 minutes until the cheese is bubbly and slightly browned.
While the chicken finishes, sauté the zucchini noodles in a pan with olive oil over medium heat for 2-3 minutes until just tender, then serve the chicken over the noodles.