Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Peel and slice the carrots and parsnips into half-inch rounds, and cube the sweet potato into one-inch pieces.
In a large mixing bowl, toss the sliced vegetables with 0.5 tablespoon of olive oil, half of the sea salt, and half of the fresh herbs.
Spread the vegetables in a single layer on one side of the prepared baking sheet.
Mince the garlic and combine it in a small bowl with the remaining olive oil, rosemary, thyme, salt, and pepper.
Rub the herb and garlic mixture evenly over the chicken breast, then place the chicken on the other side of the baking sheet.
Roast in the oven for 25 to 30 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 ensure the juices redistribute.