Preheat your oven to 400 degrees F (200 degrees C) and lightly grease a large rimmed sheet pan.
In a large bowl, toss the chicken pieces, potatoes, carrots, and red onion with half of the olive oil, mixed herbs, salt, and pepper.
Spread the chicken and sturdy vegetables evenly on the prepared sheet pan and roast for 15 minutes.
While the chicken is roasting, toss the broccoli, bell peppers, and mushrooms with the remaining olive oil.
Remove the pan from the oven, add the broccoli, peppers, mushrooms, and peas, and roast for an additional 15 minutes until the chicken reaches 165 degrees F and vegetables are tender.
Serve immediately, garnished with additional fresh herbs if desired.