Preheat your oven to 375 degrees f.
Lightly pound the chicken breasts to an even thickness and season on all sides with sea salt, pepper, and oregano.
Heat your oil in a large oven-safe skillet over medium-high heat.
Sear the chicken for 3-4 minutes per side, or just until golden brown.
Once the chicken is done, drizzle it with your marinara sauce.
Add in the tomatoes and sprinkle everything with the parmesan and mozzarella cheese.
Bake for 12 to 15 minutes, or just until the sauce is bubbly and the chicken is cooked through (the inside temperature on each should read 165F).
Just before serving garnish with fresh basil.
Enjoy!