Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel the sweet potato and cut into 1-inch cubes, then slice the carrots into 1/2-inch thick rounds.
In a large mixing bowl, toss the sweet potatoes and carrots with half of the olive oil, half of the sea salt, and half of the black pepper.
Spread the vegetables in a single layer on the prepared baking sheet and roast for 10 minutes to give them a head start.
While the vegetables are roasting, mince the garlic and finely chop the fresh rosemary and thyme.
Rub the chicken breast with the remaining olive oil, minced garlic, rosemary, thyme, and the rest of the salt and pepper.
Remove the baking sheet from the oven, move the vegetables to the sides, and place the chicken breast in the center.
Return the sheet pan to the oven and roast for another 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the tender roasted vegetables.