preheat oven to 450 degrees (beware this takes 20 minutes!)
line a baking dish with tin foil (for easy cleanup) and lightly spray with cooking spray.
dice onion and add to a small mixing bowl. Add the rest of the sauce ingredients to the mixing bowl and stir.
place chicken breasts in baking dish. cover chicken with sauce.
bake for 20 minutes or until internal temperature reaches 165 degrees.
serve with quinoa, ancient grains or your side of choice!