Preheat your oven to 400°F and lightly grease a rimmed baking sheet with the olive oil.
Place the chicken breast between two sheets of parchment paper and pound with a meat mallet until it reaches a uniform half-inch thickness.
In a shallow bowl, whisk the egg until the yolk and white are fully combined.
In a second shallow bowl, stir together the almond flour, dried oregano, garlic powder, sea salt, and black pepper.
Dip the chicken breast into the egg wash, allowing any excess to drip off, then press it firmly into the almond flour mixture to coat both sides evenly.
Place the breaded chicken onto the prepared baking sheet and bake for 15 minutes.
Remove the pan from the oven, spoon the marinara sauce over the center of the chicken, and sprinkle with the mozzarella and parmesan cheeses.
Return the chicken to the oven and broil for 2 to 3 minutes, or until the cheese is melted, bubbly, and slightly browned.