Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Prepare the ingredients by cutting the chicken breast into 1-inch bite-sized pieces and dicing the sweet potato into small 1/2-inch cubes.
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 chicken pieces, sweet potato cubes, and broccoli florets to the bowl, tossing thoroughly until every piece is well-coated in the herb oil.
Spread the mixture in a single, even layer on the prepared baking sheet, 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, tossing the ingredients halfway through, until the chicken is cooked through and the sweet potatoes are fork-tender.