Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Wash and dice the Yukon gold potato into 1/2-inch cubes and cut the chicken breast into similar bite-sized pieces.
In a large mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the diced chicken, potatoes, and broccoli florets to the bowl and toss thoroughly until every piece is evenly coated in the herb marinade.
Spread the mixture in a single layer across the prepared baking sheet, ensuring the ingredients are not overcrowded so they roast rather than steam.
Place in the oven and roast for 22-25 minutes, tossing the ingredients halfway through, until the chicken is cooked through and the potatoes are fork-tender.
Remove from the oven, garnish with finely chopped fresh parsley, and serve immediately while hot.