Preheat the oven to 425°F. Line a large baking sheet with a wire rack. Season the chicken on both sides with salt and pepper.
Set up the breading station: In one shallow bowl, whisk together the eggs. Place the flour in a second bowl. In a third bowl, combine the panko breadcrumbs, Parmesan cheese, Italian seasoning, garlic powder and a pinch of salt and pepper.
Bread the chicken: Working one piece at a time, dip the chicken into the egg wash, then coat it in the flour. Dip it again in the egg wash, then press it into the seasoned breadcrumb mixture until well coated. Repeat with all the chicken.
Pan-fry the chicken: Heat a generous layer of avocado oil in a large skillet over medium heat. Once hot, add the breaded chicken cutlets in batches, making sure not to overcrowd the pan. Cook for 2-3 minutes per side, until golden brown. Transfer the browned chicken to a wire rack set over a baking sheet. Repeat with the remaining cutlets.
Spoon marinara sauce over each piece of chicken. Top with a generous sprinkle or slice of mozzarella. Bake for 10-15 minutes, or until the cheese is melted and bubbly and the chicken reaches 165°F.