Preheat your oven to 375 degrees. This ensures that your chicken has the perfect environment to bake and become tender.
In a small bowl, combine mozzarella cheese and parmesan cheese, and set aside. This mixture will be stuffed inside the chicken, creating a cheesy center.
Take a sharp knife and carefully cut a pocket into the side of each chicken breast. Be gentle to avoid cutting through the other side.
Generously season both sides of the chicken breasts with Italian seasoning, garlic powder, salt, and pepper. This step builds flavor from the start.
Stuff about ¼ cup of the cheese mixture into each chicken breast. If you have toothpicks, seal the openings to keep the filling inside.
In a large heavy-duty pan, heat olive oil over medium-high heat. You want the pan hot enough to sear the chicken.
Add the chicken breasts to the pan. Sear for 3 to 4 minutes on each side or until they achieve a golden color.
Once seared, remove the chicken from the heat. Spoon marinara sauce over each breast, covering them well.
Top each chicken breast with a few tablespoons of the remaining cheese mixture. This will create a deliciously cheesy crust.
Finally, bake the chicken uncovered in the preheated oven for 15 to 20 minutes, or until an instant-read thermometer reads 165 degrees Fahrenheit. This ensures your chicken is cooked through and safe to eat.
Serve immediately, perhaps with a side of chopped salad, steamed veggies, or zucchini noodles for a complete meal.