Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Peel the sweet potato and cut it into 1/2-inch cubes, then chop the broccoli into bite-sized florets.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, oregano, garlic powder, sea salt, and black pepper.
Place the chicken breast, cubed sweet potatoes, and broccoli florets onto the prepared baking sheet.
Drizzle the lemon-herb marinade over the chicken and vegetables, using your hands or a spatula to toss everything until thoroughly and evenly coated.
Arrange the ingredients in a single layer, ensuring the chicken has enough space to roast properly.
Bake for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly caramelized at the edges.
Remove from the oven and let the chicken rest for 5 minutes before slicing it into strips to serve alongside the roasted vegetables.