Preheat the oven to 400°F and line a large baking sheet with parchment paper.
Place the chicken breasts on the sheet pan and rub them with smoked paprika, garlic powder, oregano, onion powder, salt, and pepper. Drizzle with 1/2 tablespoon olive oil.
In a large bowl, combine broccoli, bell pepper, and red onion. Drizzle with the remaining olive oil and season with salt and pepper. Toss well.
Spread the vegetables around the chicken on the sheet pan.
Bake for 20–25 minutes, until the chicken is fully cooked and the vegetables are tender-crisp.
Let the chicken rest for a few minutes before slicing. Garnish with minced parsley and serve.