Preheat your oven to 350°F (175°C).
In a large skillet, heat a little olive oil over medium heat. Season the chicken breasts with salt, pepper, garlic powder, onion powder, and Italian seasoning. Cook the chicken for about 5-7 minutes on each side, until fully cooked. Remove from heat and let it cool slightly.
Once cooled, chop the chicken into bite-sized pieces and place them in a mixing bowl.
In a separate bowl, whisk together the eggs and a pinch of salt. Add the eggs to the chopped chicken and mix until well combined.
Grease the casserole dish with olive oil or cooking spray. Layer the bottom of the dish with half of the marinara sauce.
Spread the chicken and egg mixture evenly over the marinara sauce.
Pour the remaining marinara sauce over the chicken, then sprinkle with half of the mozzarella cheese and half of the Parmesan cheese.
Add the rest of the mozzarella and Parmesan on top as the final layer.
Cover the casserole with aluminum foil and bake in the preheated oven for 20 minutes. After that, remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden brown.
Remove from the oven and let it cool for a few minutes before serving.