Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Trim the woody ends off the Brussels sprouts and slice them in half lengthwise.
Cut the chicken breast into uniform 1-inch bite-sized pieces to ensure even cooking.
In a large mixing bowl, combine the chicken and Brussels sprouts with olive oil, sea salt, black pepper, and garlic powder.
Toss everything thoroughly until the chicken and vegetables are evenly coated in the oil and spices.
Spread the mixture in a single layer on the prepared baking sheet, ensuring they aren't overcrowded so they roast rather than steam.
Roast for 20 to 25 minutes, tossing the ingredients halfway through, until the chicken is cooked through and the sprouts are golden brown and crispy.
Remove from the oven and drizzle the balsamic glaze over the hot chicken and sprouts before serving immediately.