Spray a rimmed baking sheet with some non-stick baking spray and lay the chicken thighs on the baking tray. Nestle in the brussels sprouts, orange slices, and red onion around the chicken thighs. Season the chicken and veggies with some salt and pepper to taste.
In a small bowl, whisk orange juice, olive oil, honey, and garlic with salt and pepper to taste.
Pour the glaze over the chicken and veggies and massage to evenly coat everything with the orange glaze.
Place in the oven to roast until the chicken is fully cooked through and the brussels sprouts are golden-brown and crisp, around 25-30 minutes. Sprinkle with reserved orange zest. Serve with warm crusty bread topped with cinnamon-honey butter. Enjoy!