Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Dice the sweet potato into 1/2-inch cubes and slice the carrots into 1/2-inch thick rounds.
Finely mince the garlic cloves and place them in a large mixing bowl.
Add the chicken breast, cubed sweet potatoes, and sliced carrots to the bowl with the garlic.
Drizzle the olive oil over the ingredients and sprinkle with the dried rosemary, thyme, sea salt, and black pepper.
Toss everything thoroughly until the chicken and vegetables are evenly coated in the oil and herbs.
Spread the mixture in a single layer on the prepared baking sheet, ensuring there is space between the pieces to allow for roasting rather than steaming.
Roast for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the root vegetables are fork-tender and caramelized.
Remove from the oven and let the chicken rest for 5 minutes before slicing it to serve alongside the roasted vegetables.