Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Peel the sweet potato, carrots, and parsnips, then dice them into uniform 1-inch cubes to ensure even roasting.
Mince the fresh garlic clove finely.
In a large mixing bowl, combine the diced root vegetables and the chicken breast.
Drizzle the olive oil over the chicken and vegetables, then sprinkle with rosemary, thyme, sea salt, black pepper, and minced garlic.
Toss everything thoroughly until the chicken and vegetables are well-coated in the oil and herb mixture.
Spread the ingredients in a single layer on the prepared baking sheet, ensuring the chicken pieces are not crowded by the vegetables.
Roast in the center of the oven for 25-30 minutes, or until the chicken reaches an internal temperature of 165°F and the root vegetables are tender and golden-brown.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy.
Plate the sliced chicken alongside the roasted vegetables and serve immediately.