Preheat oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel and dice the carrots, parsnips, and sweet potato into 1-inch cubes to ensure even roasting.
Finely mince the fresh rosemary, thyme, and garlic clove.
In a large mixing bowl, combine the diced vegetables and chicken breast with olive oil, minced herbs, garlic, salt, and pepper.
Toss thoroughly until everything is evenly coated in the herb oil.
Spread the mixture in a single layer on the prepared baking sheet, making sure the chicken pieces are not crowded.
Roast for 25-30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and golden-brown.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted root vegetables.