Preheat the oven to 400 degrees F.
Make the marinade: in a bowl, whisk together the maple syrup, Dijon, mayo, olive oil, salt, and pepper. Add the chicken thighs, toss to coat, and refrigerate for 20 minutes.
Peel and dice the sweet potatoes. Add to a bowl and toss with 1 tablespoon olive oil, the salt, pepper, cinnamon, and cumin.
Spread the sweet potatoes on a lined baking sheet and bake for 20 minutes.
Meanwhile, trim and halve the Brussels sprouts and toss in a bowl with the remaining 1 tablespoon olive oil, salt, and pepper.
Remove the sweet potatoes, toss, push them to one side of the pan, and add the Brussels sprouts.
Bake for another 20 minutes, then broil for 1 to 2 minutes until everything is crisp.
Meanwhile, air fry the chicken at 390 degrees F for 10 minutes, then flip and cook for another 8 minutes, until cooked through (165 degrees F).
Assemble bowls with the sweet potatoes, Brussels sprouts, chicken, and diced apple. Drizzle with honey mustard and serve.