Preheat your oven to 375 degrees Fahrenheit. Lightly grease a 9×13 inch baking dish.
Prepare the chicken breading stations. Place flour in one shallow dish. Whisk eggs in a second dish. In a third dish, combine panko breadcrumbs, 1/4 cup of the Parmesan cheese, garlic powder, salt, and pepper.
Dredge each thin chicken cutlet first in flour, shaking off excess. Dip into the egg mixture, letting excess drip off. Coat thoroughly in the panko mixture, pressing gently to adhere.
Heat the vegetable oil in a large skillet over medium-high heat. Cook the breaded chicken in batches for 3 to 4 minutes per side until golden brown and cooked through. Remove chicken and place on a paper towel-lined plate. Let cool slightly, then slice each piece into bite-sized chunks suitable for the sliders.
Slice the slider buns horizontally, keeping the top and bottom halves intact in their cluster. Place the bottom halves in the prepared baking dish.
Layer the ingredients on the bottom buns: spread a thin layer of marinara sauce on each bottom bun half. Top with the crispy chicken pieces. Place a slice or sprinkle of mozzarella cheese over the chicken on each bun.
Replace the top halves of the buns. In a small bowl, mix the melted butter with the remaining 1/4 cup of Parmesan cheese and Italian seasoning. Brush this mixture evenly over the tops of the assembled sliders.
Cover the baking dish tightly with aluminum foil. Bake for 15 minutes.
Remove the foil and bake for an additional 5 to 7 minutes, or until the cheese is fully melted and bubbly.
Slice the sliders apart and serve immediately.
Notes
For extra crispiness, you can air fry the breaded chicken instead of pan-frying. Cook at 380 degrees Fahrenheit for 10-12 minutes, flipping halfway.
Use your favorite store-bought or homemade marinara sauce.
If you prefer a sharper flavor, substitute some of the mozzarella with provolone cheese.