Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Pat the chicken breast dry with paper towels to ensure a crispy exterior, then season with half of the olive oil, rosemary, garlic powder, sea salt, and black pepper.
Peel and dice the sweet potato into 1-inch cubes, tossing them in a bowl with the remaining olive oil and a pinch of salt.
Arrange the chicken and sweet potatoes on the prepared baking sheet, ensuring they are in a single layer, and roast for 15 minutes.
Add the broccoli florets and sliced carrots to the sheet pan, squeeze the fresh lemon juice over the chicken and vegetables, and roast for another 10-12 minutes.
Check that the chicken has reached an internal temperature of 165°F and the vegetables are tender before removing from the oven.
Allow the chicken to rest for 5 minutes to lock in the juices before slicing and serving with the roasted vegetables.