Preheat the oven to 425°F (220°C). In a large bowl, combine the chicken chunks, melted butter, minced garlic, salt, and pepper, mixing well to evenly coat the chicken.
Thread the marinated chicken chunks evenly onto 6 skewers, leaving a little space between each piece for even cooking.
Place the skewers on a disposable aluminum baking tray (so air can circulate around them) and lay fresh rosemary sprigs on top of the chicken pieces.
Bake for about 15 minutes, removing rosemary before flipping halfway through for even browning on all sides.
Once the chicken is cooked through and lightly charred, remove from the oven, remove the rosemary sprigs, and let cool slightly before serving.