Preheat the oven to 400°F (200°C). Line a baking sheet with foil and place a wire rack on top; lightly spray the rack with nonstick cooking spray.
Pat the chicken pieces dry with paper towels, then season with salt and pepper. Place the chicken in a medium bowl and pour the buttermilk over it; toss to coat and set aside to marinate briefly.
In a shallow dish, combine the panko breadcrumbs, grated parmesan, and Italian seasoning; mix well.
Set up three more shallow dishes: one with the all-purpose flour, one with the melted butter, and one with the lightly beaten eggs, for a total of four dredging stations (flour, butter, eggs, breadcrumb mixture).
Remove the chicken from the buttermilk using a mesh strainer and allow excess liquid to drip off.
Dredge each chicken piece in flour, shaking off excess, then dip in melted butter, followed by the beaten eggs, and finally coat thoroughly in the panko-parmesan mixture. Place coated pieces on the prepared wire rack.
Bake on the middle rack for 20 minutes, then turn each nugget and bake an additional 10 minutes until golden brown and cooked through (internal temperature 165°F/74°C).
If you want extra crispness, broil for 1–3 minutes after baking, watching closely to avoid burning.