Preheat oven to 375°F. Place chicken, broccoli, and sweet potato cubes in a 9×13 glass baking dish. Drizzle olive oil over them and stir to evenly coat.
Spread out the chicken evenly in the dish and spread the veggies around and on top of the chicken evenly. Sprinkle the garlic powder, oregano, salt, and pepper on top.
Bake in preheated oven for 45 minutes, uncovered. Remove from oven and let chicken rest a few minutes before serving to keep the juices inside.