Preheat your oven to 400°F (200 °C) and line a large baking sheet with parchment paper for easy cleanup.
Wash and trim the ends of the Brussels sprouts, then slice them in half vertically to ensure they get maximum surface area for browning.
Cut the chicken breast into uniform 1-inch cubes so they cook evenly alongside the vegetables.
In a large mixing bowl, combine the halved Brussels sprouts and chicken pieces.
Drizzle with the extra virgin olive oil and sprinkle with the sea salt, black pepper, and garlic powder.
Toss the mixture thoroughly until every piece is well-coated in the oil and seasonings.
Spread the chicken and sprouts in a single layer on the prepared baking sheet, ensuring they are not overcrowded.
Roast in the oven for 20 to 25 minutes, tossing halfway through, until the chicken is cooked through and the sprouts are charred and crispy.
Remove from the oven and immediately drizzle the balsamic glaze over the hot chicken and vegetables.
Toss one final time on the pan to distribute the glaze and serve immediately while warm.