Preheat your oven to 400°F and lightly coat a baking sheet with the olive oil to prevent sticking.
Place the chicken breast between two sheets of parchment paper and pound to an even half-inch thickness for uniform cooking.
In a shallow bowl, whisk the egg until well combined.
In a separate shallow dish, mix together the panko breadcrumbs, parmesan cheese, garlic powder, oregano, sea salt, and black pepper.
Dip the chicken breast into the egg wash, allowing any excess to drip off, then press firmly into the panko mixture until thoroughly coated on both sides.
Place the breaded chicken on the prepared baking sheet and bake for 15 minutes until the crust is golden and the chicken is nearly cooked through.
Remove the pan from the oven and spoon the marinara sauce over the center of the chicken, then sprinkle the shredded mozzarella on top.
Return the chicken to the oven for an additional 5 to 7 minutes until the cheese is melted, bubbly, and slightly browned.