Preheat the oven to 425°F (220°C) and lightly grease a large baking dish or sheet pan.
Pat the chicken dry. Drizzle with olive oil and season with garlic powder, paprika, Italian seasoning, onion powder, salt, and pepper.
Toss the broccoli, carrots, zucchini, and red onion with olive oil, garlic powder, and salt.
Arrange the chicken and vegetables on the pan without overcrowding.
Bake for 20 to 25 minutes, until the thickest part of the chicken reaches 165°F (74°C).
Let the chicken rest for 5 minutes, then slice and serve with the roasted vegetables.