Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Peel and chop the carrots and parsnips into 1-inch pieces, and halve the Brussels sprouts.
In a large mixing bowl, toss the vegetables with half of the olive oil, half of the sea salt, and half of the black pepper until well coated.
Spread the seasoned vegetables in a single layer on one side of the prepared baking sheet.
In a small bowl, combine the remaining olive oil, minced garlic, chopped rosemary, and thyme to create a herb rub.
Coat the chicken breast thoroughly with the herb rub and place it on the other side of the baking sheet.
Roast in the center of the oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and golden.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted vegetables.