Prep all your vegetables: chop the tomatoes, onions, and peppers; mince the garlic. Whisk the egg in a small bowl. Place the chicken between plastic wrap and use a meat mallet to flatten to about ½ inch thick, then cut into quarters. Preheat the oven to 425°F.
In a small bowl, combine the panko breadcrumbs and chopped parsley. In another small bowl, mix the flour with salt to taste. Dredge the chicken in the flour, then dip into the whisked egg, shaking off the excess before coating completely with the panko mixture. Season with salt and pepper, to taste.
Heat 2-3 tablespoons of vegetable oil over medium-high heat. Place the panko-crusted chicken in the hot oil and sear on both sides until cooked through, about 3-4 minutes per side. Remove the chicken from the pan and set aside. Wipe the skillet clean.
Add a tablespoon of vegetable oil to the skillet. Add the onions and sauté for 2-3 minutes, until tender. Then add the garlic and cook until fragrant. Stir in the peppers and cook for 3-4 minutes, until softened.
Pour in the diced tomatoes and stir as they release their moisture. Let as much of the moisture evaporate as you can - when cooked sufficiently, it should be mostly dry when a spoon is scraped down the center of the skillet.
Season the tomato mixture with oregano, thyme, garlic powder, and onion powder. Season with salt and pepper, as desired. Reduce the heat to barely a simmer and pour in the tomato sauce. Stir well to combine and heat through, then add the tomato paste to thicken the sauce. Simmer for about 10 minutes on medium-low heat.
Bring a pot of water to a boil. Cook the pasta according to the instructions on the box. Cut the mozzarella into ½ inch thick slices.
Add the chicken to the sauce and place a slice of mozzarella on top of each piece. Place in the oven and cook until the mozzarella is bubbly and melted. Optionally, broil until browning and bubbled.
Serve the chicken and sauce on a bed of noodles or alongside a simple Caesar salad. Enjoy!