01 - Preheat oven to 400°F. Line a baking sheet with parchment paper or lightly grease it.
02 - Place chicken breasts between two sheets of plastic wrap. Using a meat mallet, pound each breast to an even thickness of about 3/4 inch.
03 - Season both sides of each chicken breast evenly with garlic powder, onion powder, paprika, salt, and black pepper.
04 - Arrange three shallow bowls: place flour in the first, beat the eggs with milk in the second, and combine panko breadcrumbs with 1/2 cup grated Parmesan in the third.
05 - Dredge each seasoned chicken breast in flour, shaking off excess. Dip into the egg mixture, then press firmly into the panko-Parmesan blend, ensuring full even coverage on all sides.
06 - Heat a thin layer of oil in a large skillet over medium-high heat. Sear the breaded chicken breasts for 2 to 3 minutes per side until golden brown and crispy.
07 - Transfer the seared chicken to the prepared baking sheet. Bake for 15 to 20 minutes, or until the internal temperature reaches 165°F.
08 - While the chicken bakes, combine ranch dressing, 1/4 cup grated Parmesan cheese, and chopped parsley in a small mixing bowl. Stir until well blended.
09 - Remove the chicken from the oven. Spoon the ranch Parmesan sauce evenly over each breast. Sprinkle shredded Monterey Jack and shredded Parmesan generously on top.
10 - Return the chicken to the oven and broil for 2 to 3 minutes until the cheese is fully melted and bubbly. Serve hot, garnished with additional fresh parsley if desired.