Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Cut the boneless skinless chicken breast into 1-inch bite-sized pieces and place them in a large mixing bowl.
Chop the sweet potato into small cubes, slice the bell pepper into strips, and break the broccoli into small florets, then add them to the bowl with the chicken.
In a small jar or bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper until well combined.
Pour the lemon-herb marinade over the chicken and vegetables, tossing thoroughly to ensure every piece is evenly coated.
Spread the mixture across the prepared baking sheet in a single layer, making sure not to overcrowd the pan so the vegetables roast rather than steam.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the sweet potatoes are tender and lightly browned.
Remove from the oven and sprinkle with freshly chopped parsley before serving warm.