Preheat your oven to 400°F.
Pat the chicken breast dry, then season it with salt and pepper on both sides.
Place the chicken on a baking sheet lined with parchment paper.
In a bowl, toss the halved Brussels sprouts with olive oil, salt, and pepper until evenly coated.
Spread the Brussels sprouts on a separate baking sheet in a single layer.
Roast both the chicken and Brussels sprouts in the preheated oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the sprouts are tender and slightly crispy.
While the vegetables roast, heat the balsamic vinegar in a small saucepan over medium heat until it slightly reduces and thickens into a glaze, about 3-5 minutes.
Once cooked, plate the roasted chicken and Brussels sprouts, then drizzle the balsamic glaze over the sprouts.
Serve immediately and enjoy your balanced, flavorful meal.