On the pan, combine the broccoli, sweet potato, onion, garlic, raisins and walnuts. Drizzle with oil, add seasonings, salt and pepper and toss to coat. Spread evenly amongst the pan, cover with foil and bake for 12 minutes.
After the 12 minutes remove from oven, add chicken, toss and place back in oven to bake for another 8 minutes. Then again remove from oven, toss once more and place back in oven without foil this time and bake for another 5-10 minutes or until chicken is cooked through and sweet potatoes are soft.