Preheat oven to 425°F (220°C).
Prepare the sweet potato, Brussels sprouts, carrots, and red onion.
Whisk olive oil, Dijon, maple syrup, garlic, rosemary, thyme, paprika, salt, and pepper.
Toss vegetables with approximately half the seasoning.
Pat chicken dry and coat with remaining seasoning.
Arrange chicken and vegetables in a single layer on a large sheet pan.
Roast for 15 minutes.
Core and cut the apple into thick wedges.
Turn the vegetables and add the apple.
Roast another 10–15 minutes, until the chicken reaches at least 165°F (74°C) and the vegetables are tender.
Broil for 1–2 minutes if additional browning is desired.
Rest chicken for 5 minutes.
Garnish with additional fresh herbs and serve.