Preheat your oven to 425°F (218°C) and line a baking sheet with parchment paper.
Trim the ends off the Brussels sprouts and slice them in half vertically.
Pat the chicken thighs completely dry with a paper towel; this is the secret to achieving a perfectly crispy skin.
In a large mixing bowl, combine the chicken, halved Brussels sprouts, olive oil, sea salt, black pepper, chopped rosemary, thyme, and minced garlic.
Toss everything together until the chicken and vegetables are evenly coated in the oil and herbs.
Arrange the chicken thighs skin-side up on the baking sheet and scatter the Brussels sprouts around them in a single layer.
Roast for 25 to 30 minutes, or until the chicken skin is golden and crispy and the sprouts are tender with charred edges.
Remove from the oven and let the chicken rest for 5 minutes before serving to ensure it remains juicy.