Preheat oven to 350 degrees.
Pat chicken dry with paper towels then place it in a large roasting pan. Sprinkle liberally on all sides with next 5 ingredients (chili through thyme); set aside.
In a small bowl, whisk together brown sugar, lemon juice, olive oil, salt and pepper until sugar has dissolved. Arrange red
onions and sweet potatoes around the chicken.
Brush chicken and veggies with brown sugar mixture; roast for 1 hour or until chicken is cooked through and veggies are tender. Serve with a drizzle of pan juices.