Preheat oven to 425°F and line a large sheet pan with parchment paper or cooking spray.
In a large bowl, combine melted butter, minced garlic, ½ cup Parmesan cheese, Italian seasoning, paprika, salt, and pepper.
Add chicken cubes, halved potatoes, and broccoli to the bowl. Toss everything together until well coated with the garlic-parmesan mixture.
Spread everything in a single layer on the prepared sheet pan, making sure the potatoes are cut-side down for better browning.
Bake for 18-20 minutes until the chicken reaches 165°F internally and the potatoes are fork-tender.
Remove from oven and sprinkle with remaining Parmesan cheese and fresh parsley. Let rest for 2 minutes before serving.