Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel the sweet potato and cut it into 1-inch cubes, then toss them directly on the baking sheet with 0.5 tablespoons of olive oil and a pinch of salt.
Spread the sweet potatoes into a single layer and roast for 10 minutes to give them a head start.
While the potatoes roast, mince the garlic and finely chop the fresh rosemary.
Rub the chicken breast with the remaining 0.5 tablespoons of olive oil, minced garlic, chopped rosemary, sea salt, and black pepper.
Remove the baking sheet from the oven, slide the potatoes to one side, and place the chicken breast and broccoli florets on the other side.
Return the sheet to the oven and roast for 18-22 minutes, or until the chicken reaches an internal temperature of 165°F and the broccoli is slightly charred.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure the juices redistribute for a moist result.