Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Slice the chicken breasts in half horizontally to create thinner pieces.
In a shallow dish, mix the breadcrumbs, grated Parmesan cheese, dried oregano, garlic powder, salt, and pepper.
Set up a dredging station with one bowl of flour, another bowl of beaten eggs, and the breadcrumb mixture.
Coat each chicken piece in flour, dip it into the beaten eggs, and finally coat it with the breadcrumb mixture.
Heat a large skillet over medium heat and add a tablespoon of oil. Cook the coated chicken pieces for about 3-4 minutes on each side until golden brown and cooked through.
Transfer the cooked chicken pieces to the prepared baking sheet, spoon marinara sauce over each piece, and top with a slice of mozzarella cheese.
Bake in the preheated oven for 10 minutes until the cheese is melted and bubbly.
Lightly toast the slider buns in the oven for the last 5 minutes of baking.
Assemble the sliders by placing a piece of chicken on the bottom half of each toasted bun, adding more marinara sauce if desired, and topping with fresh basil leaves. Cover with the top half of the bun.