In a medium bowl whisk together honey, both mustards, garlic, salt, and pepper.
Place chicken breast in marinade and let it sit for about 3 hours or overnight.
Preheat oven to 375 degrees.
Place the chicken and brussel sprouts on opposite ends of the sheet pan.
Bake for 30 -40 minutes or until the chicken is no longer pink in the middle and juices run clear. The middle temperature should be 165 degrees.
Serve with rice, quinoa, or as is.