Preheat oven to 450°F.
Combine the Brussels sprouts, squash, onion, lemon slices and minced garlic in a large bowl.
Add 2 Tablespoons of olive oil, balsamic vinegar, 1 teaspoon salt, 1 teaspoon pepper and nutmeg and toss to combine.
Spread veggie mixture onto a large baking sheet.
Combine remaining olive oil, apple cider vinegar, fennel seeds, red pepper, paprika, garlic powder, ½ teaspoon sea salt, ½ teaspoon pepper and sage in a small bowl. Coat chicken with the marinade and arrange chicken on top of the Brussels sprouts and squash mixture.
Bake for 30-40 minutes or until both the veggies and chicken are cooked through.
Portion onto plates, squeeze any remaining juice from the lemon over each serving and enjoy!
Leftovers will last up to five days in the refrigerator. To reheat, I recommend spreading the leftovers on a sheet pan and reheating in the oven. If you're in a rush, the microwave will work but the vegetables won't be as crispy.