Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Dice the sweet potato and carrot into uniform 1/2-inch cubes to ensure they cook at the same rate.
Slice the zucchini into half-moons and break the broccoli into small, bite-sized florets.
Mince the garlic cloves finely and strip the rosemary leaves from the stem, chopping them until fragrant.
Place the chicken breast and all the prepared vegetables onto the baking sheet in a single layer.
Drizzle the olive oil over the chicken and vegetables, then sprinkle evenly with the minced garlic, chopped rosemary, sea salt, and black pepper.
Use your hands or tongs to toss everything together until thoroughly coated in the oil and seasonings.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure it stays juicy and flavorful.