Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Pat the chicken breast completely dry with a paper towel to ensure the skin or surface achieves a golden crisp.
Peel and dice the sweet potato into 1/2-inch cubes and chop the broccoli into bite-sized florets.
Mince the garlic clove and finely chop the fresh rosemary leaves.
In a large mixing bowl, toss the chicken breast, sweet potato cubes, and broccoli florets with the olive oil, minced garlic, rosemary, sea salt, and black pepper.
Spread the chicken and vegetables onto the prepared baking sheet in a single layer, ensuring they are not overcrowded.
Squeeze the juice of the half lemon over the chicken breast and place the squeezed lemon wedge on the tray for extra aroma.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep the meat juicy.