Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel and chop the carrots, parsnips, and sweet potato into uniform 1-inch cubes to ensure even roasting.
In a large mixing bowl, toss the root vegetables with half of the olive oil, half of the sea salt, and half of the black pepper.
Spread the seasoned vegetables in a single layer across the prepared baking sheet, leaving space in the center for the chicken.
Pat the chicken breast dry with paper towels, then rub it thoroughly with the remaining olive oil, minced garlic, rosemary, thyme, salt, and pepper.
Place the chicken breast in the center of the baking sheet nestled among the vegetables.
Roast in the oven for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are golden and tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted roots.