Combine the onion, brown sugar, soy sauce, vinegar, thyme, oil, garlic, allspice and habanero pepper in the container of a food processor or blender. Process until smooth. Place the chicken into a large resealable bag, and pour in 3/4 of the sauce. Squeeze out excess air, and seal. Marinate in the refrigerator for at least one hour.

Preheat your oven's broiler.

Remove chicken from bag, and discard marinade. Broil chicken for 10 to 15 minutes, turning once to ensure even cooking. Heat remaining sauce in a small pan, and pour over chicken when serving.

Heat the oven to 400.

Cut the sweet potatoes into sticks 1/4 to 1/2 inch wide and 3 inches long, and toss them with the oil.

Mix the spices, salt, and pepper in a small bowl, and toss them with the sweet potatoes. Spread them out evenly on a baking sheet.

Bake until brown and crisp on the bottom, about 15 minutes, then flip and cook until the other side is crisp, about 10 minutes.

Serve.