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 each one in half vertically.
Cut the chicken breast into 1-inch bite-sized pieces to ensure they cook at the same rate as the vegetables.
In a large mixing bowl, combine the chicken pieces and halved sprouts with the olive oil, sea salt, black pepper, and garlic powder.
Toss everything thoroughly until the chicken and sprouts are evenly coated in the oil and seasonings.
Spread the mixture onto the prepared baking sheet in a single layer, turning the Brussels sprouts cut-side down to achieve maximum caramelization.
Roast for 22 to 25 minutes, tossing the pan halfway through, until the chicken is cooked through and the sprouts are tender with charred edges.
Transfer the roasted chicken and sprouts to a serving plate and drizzle immediately with the balsamic glaze.