Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
In a small mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken breast, broccoli florets, and sliced carrots onto the prepared sheet pan.
Pour the lemon-herb marinade over the chicken and vegetables, using your hands or tongs to toss until everything is thoroughly and evenly coated.
Spread the ingredients out into a single layer, ensuring the chicken is in the center and the vegetables have enough space to roast rather than steam.
Place the pan in the oven and roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy, then serve immediately with the roasted vegetables.