Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Chop the carrots and parsnips into 1-inch rounds, and halve the Brussels sprouts.
Mince the garlic and finely chop the fresh rosemary and thyme leaves.
In a large bowl, whisk together the olive oil, minced garlic, rosemary, thyme, sea salt, and black pepper.
Add the chicken breast and chopped vegetables to the bowl, tossing thoroughly to ensure everything is evenly coated in the herb oil.
Spread the mixture in a single layer on the prepared sheet pan, ensuring the chicken has enough space to roast evenly.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly browned.
Remove from the oven and let the chicken rest for 5 minutes before slicing and serving alongside the roasted vegetables.