Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Chop the carrots and sweet potato into uniform 1-inch cubes to ensure even roasting.
Mince the garlic and finely chop the fresh rosemary leaves.
In a large mixing bowl, combine the chicken breast, carrots, and sweet potatoes.
Drizzle with olive oil and add the minced garlic, rosemary, sea salt, and black pepper, tossing thoroughly to coat every piece.
Spread the chicken and vegetables in a single layer on the prepared baking sheet, ensuring they aren't crowded.
Roast for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly caramelized.
Allow the chicken to rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted roots.