Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper for easy cleanup.
Wash and peel the sweet potato, then dice it into uniform 1/2-inch cubes to ensure even roasting.
Trim the ends of the green beans and break the broccoli into bite-sized florets.
In a small bowl, whisk together the olive oil, minced garlic, rosemary, thyme, sea salt, and black pepper.
Place the chicken breast, sweet potato cubes, broccoli, and green beans onto the prepared sheet pan.
Drizzle the garlic-herb oil mixture over everything and use your hands or tongs to toss until every piece is well-coated.
Spread the ingredients out into a single layer, making sure the chicken breast is in the center and not covered by vegetables.
Roast in the oven 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 and flavorful.