01 - Preheat oven to 400°F.
02 - In a large mixing bowl, combine halved Brussels sprouts with olive oil, a generous pinch of salt, and freshly ground black pepper. Toss well to evenly coat.
03 - Transfer seasoned Brussels sprouts to a rimmed sheet pan, spreading in an even layer. Nestle chicken thighs among the sprouts, skin side up. Sprinkle chicken with additional salt, pepper, and minced garlic.
04 - Place the sheet pan in the preheated oven and roast for 20 minutes.
05 - Remove pan from oven. Drizzle balsamic vinegar evenly over chicken and Brussels sprouts. Return to oven and roast an additional 15–20 minutes, or until chicken skin is crisp and internal temperature reaches 165°F.
06 - Let rest 5 minutes before serving. Plate chicken thighs with Brussels sprouts. For added flavor and texture, sprinkle toasted walnuts over the dish just before serving.