Preheat oven to 425°F. Line large baking sheet with foil or parchment.
Pound chicken to even thickness if very thick.
Mix 2 tablespoons olive oil with garlic powder, paprika, oregano, salt, and pepper.
Rub seasoning all over chicken breasts.
Toss all vegetables except broccoli with 2 tablespoons olive oil, salt, and pepper.
Arrange vegetables in single layer on pan. Leave space in center.
Place chicken in center among vegetables.
Roast 20 minutes.
Add broccoli. Toss vegetables gently.
Roast 12 to 15 more minutes until chicken reaches 165°F.
Let chicken rest 5 minutes.
Garnish with parsley. Serve with lemon wedges.