Preheat your oven to 400°F (200°C) 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 roasting.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a large mixing bowl, combine the diced chicken breast and chopped root vegetables.
Drizzle with extra virgin olive oil and sprinkle with the minced garlic, fresh herbs, sea salt, and black pepper.
Toss everything thoroughly until the chicken and vegetables are well-coated in the oil and aromatics.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the pieces aren't overcrowded.
Roast for 25 to 30 minutes, tossing the vegetables halfway through, until the chicken is cooked through and the vegetables are golden brown.
Remove from the oven and let the chicken rest for 5 minutes before serving to keep it juicy.