Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper for easy cleanup.
Peel the sweet potato and cut it into 1/2-inch cubes, then chop the chicken breast into similar bite-sized pieces.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken cubes, sweet potato cubes, and broccoli florets onto the prepared sheet pan.
Pour the lemon-herb dressing over the chicken and vegetables, tossing thoroughly with tongs to ensure an even coating.
Spread the mixture out into a single layer, making sure the pieces are not overlapping so they 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 when pierced with a fork.
Remove from the oven and garnish with finely chopped fresh parsley before serving or packing into meal prep containers.