Preheat your oven to 425°F.
Trim the ends of the Brussels sprouts and cut any large ones in half for even cooking.
In a bowl, whisk together the honey, balsamic vinegar, olive oil, garlic powder, salt, and pepper.
Toss the Brussels sprouts in half of the glaze until they are well coated.
Spread the Brussels sprouts on a baking sheet in a single layer and roast in the oven for about 20-25 minutes, stirring halfway through, until crispy and caramelized.
While the Brussels sprouts roast, season the chicken breast with salt, pepper, and a light sprinkle of garlic powder.
Preheat a grill pan or skillet over medium-high heat and grill the chicken for about 6-7 minutes per side, or until the internal temperature reaches 165°F.
Once the chicken is done, let it rest for a few minutes, then slice it.
Drizzle the remaining glaze over the roasted Brussels sprouts, toss gently, and serve alongside the sliced grilled chicken.