Preheat and prep: Heat your oven to 400°F (200°C).
Lightly oil a large baking dish or sheet pan. Pat the chicken dry with paper towels.
Make the marinade: In a bowl, whisk together Greek yogurt, olive oil, lemon zest, lemon juice, garlic, dried oregano, dried thyme, 1 teaspoon salt, and black pepper. Stir in half of the chopped fresh herbs.
Coat the chicken: Add the chicken to the bowl and toss to coat.
Let it sit while you prep the vegetables, or refrigerate for up to 30 minutes for deeper flavor.
Season the vegetables: In the baking dish, toss broccoli, bell pepper, red onion, and cherry tomatoes with a drizzle of olive oil, a pinch of salt and pepper, and a squeeze of lemon if you like.
Assemble the pan: Nestle the chicken on top of the vegetables. Spoon any remaining marinade over the chicken. Add lemon slices around the pan for aroma.
Bake: Roast for 22–28 minutes, depending on the thickness of the chicken. Chicken is done at 165°F (74°C) internal temperature. The vegetables should be tender with slightly crisp edges.
Optional protein boost: If using chickpeas, scatter them around the pan for the last 10–12 minutes of baking.
If using cooked quinoa, warm it separately or toss it in the pan juices after baking.
Finish: Let the chicken rest 5 minutes. Sprinkle with the remaining fresh herbs, and add Parmesan or feta if using. Taste and adjust salt, pepper, or lemon juice.
Serve: Spoon the vegetables and pan juices into bowls, top with sliced chicken, and finish with a pinch of red pepper flakes for gentle heat.