Preheat the Oven: Set your oven to 400°F (200°C). Line a large rimmed baking sheet with parchment paper or lightly grease it to prevent sticking.
Make the Marinade: In a sizable mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, lemon zest, minced garlic, dried oregano, dried thyme, and a generous pinch of salt and pepper.
Marinate the Chicken: Add the chicken breasts to the marinade, making sure each piece is generously coated. Allow the chicken to marinate for at least 15 minutes while you prepare the vegetables.
Prepare the Vegetables: In a separate bowl, toss the halved Brussels sprouts, quartered baby potatoes, and sliced bell peppers with a light drizzle of olive oil, as well as salt and pepper to taste.
Arrange on the Baking Sheet: Place the marinated chicken breasts on one side of the prepared baking sheet. On the opposite side, spread the seasoned vegetables out evenly.
Bake the Meal: Slide the baking sheet into the preheated oven and bake for 25-30 minutes.
Broil for Extra Crispness: If you desire a beautiful golden-brown finish, switch to the broil setting for an additional 2-3 minutes.
Rest and Garnish: Once cooked, remove the baking sheet from the oven and let it rest for 5 minutes. Just before serving, sprinkle chopped fresh parsley over everything.