Preheat oven to 400°F.
Peel and chop the sweet potato and carrots into uniform 1-inch pieces.
In a large bowl, toss the vegetables with half of the olive oil, half of the rosemary, half of the thyme, and a pinch of salt and pepper.
Spread the vegetables in a single layer on a parchment-lined baking sheet and roast for 15 minutes.
While vegetables roast, season the chicken breast with garlic powder, the remaining rosemary, thyme, salt, and pepper.
Heat the remaining olive oil in a large skillet over medium-high heat and sear the chicken for 3 minutes per side until a golden crust forms.
Move the vegetables to the sides of the baking sheet and place the seared chicken in the center.
Return the sheet to the oven and roast for an additional 12 to 15 minutes until the chicken reaches an internal temperature of 165°F.
Remove from the oven and allow the chicken to rest for 5 minutes to lock in the juices.
Slice the chicken and serve alongside the tender, herb-crusted root vegetables.