Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Dice the sweet potato and carrots into 1/2-inch cubes to ensure they roast evenly with the chicken.
In a large bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the chicken breast, cubed sweet potato, carrots, and broccoli florets to the bowl and toss thoroughly until everything is well-coated in the herb oil.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the chicken has enough space around it.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly browned.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve immediately.