Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Peel and dice the sweet potato, carrots, and parsnips into uniform 1-inch cubes to ensure even cooking.
Mince the garlic clove and finely chop the fresh rosemary and thyme leaves.
In a large mixing bowl, toss the diced root vegetables with 0.5 tablespoon of olive oil, half of the minced garlic, and half of the herbs, salt, and pepper.
Coat the chicken breast with the remaining 0.25 tablespoon of olive oil and rub with the remaining garlic, herbs, salt, and pepper.
Spread the seasoned vegetables in a single layer on the prepared baking sheet, leaving space in the center for the chicken.
Place the chicken breast in the middle of the vegetables and roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F.
Remove from the oven and let the chicken rest for 5 minutes before slicing and serving with the caramelized root vegetables.