Preheat the oven to 400F. Move the rack to the top third of the oven. Boil a salted pot of water for the pasta if that's what you're serving it with. Cook the pasta al dente according to package directions.
Cut the chicken in half lengthwise so you have 4 thinner pieces. Pat it dry with paper towel. Sprinkle it with the garlic powder and some salt & pepper (both sides).
Prepare 3 bowls: one with the flour, one with the eggs (beat them with a fork), and the third with the panko + parmesan + Italian seasoning (mix it all together).
Add the marinara sauce to a saucepan and warm it over low heat (it needs to be hot for step 8).
Add 2 tablespoons of olive oil to a skillet over medium heat. Let the pan heat up while you're doing the next step.
Meanwhile, coat the chicken pieces in the flour. You will then dip each piece in the egg, followed by the breadcrumb mixture (shake off any excess at each of the 3 steps). I find it easiest to do the dipping with one hand and leaving the other one free (or your hands get messy and it's all harder to work with). You may need to press the chicken into the breadcrumbs a bit to make them stick.
Add 2 chicken pieces to the skillet (give them lots of space) and cook for about 2-3 minutes/side (should be golden and crispy). I use tongs to easily flip it. Transfer the chicken to a plate, and for the second batch, add another tablespoon of oil to the pan. Once you've fried all the chicken, take the skillet off the heat and arrange all 4 pieces inside. Transfer the skillet to the oven and bake for 5 minutes.
Take the skillet out of the oven. Turn the broiler onto high. Spoon a bit of hot marinara sauce over top of each piece of chicken (I top each piece with about 2 tablespoons of sauce and reserve the rest for tossing with the pasta). I don't add too much sauce because then the breading will go soggy (don't put so much that it runs off). Top the chicken with the mozzarella cheese and return the skillet to the oven. Let the cheese melt/go bubbly (this will only take a few minutes - watch it carefully so it doesn't burn). Meanwhile, toss the drained pasta with the remaining marinara sauce.
Serve immediately with pasta on the side and some fresh basil if you wish.