Creating a delicious Greek Chicken Sheet Pan Dinner is straightforward when you follow these easy steps:

1. Preheat the Oven: Preheat your oven to 400°F (200°C).
2. Prep the Vegetables: On a large sheet pan, add the sliced red onion, bell pepper, zucchini, and cherry tomatoes. Toss with half of the olive oil, lemon juice, salt, and pepper.
3. Prepare the Chicken: In a separate bowl, mix the remaining olive oil, garlic, oregano, lemon juice, salt, and pepper. Coat the chicken breasts in this mixture.
4. Arrange the Chicken: Place the seasoned chicken breasts on top of the vegetables in the sheet pan.
5. Add Olives and Feta: Scatter the Kalamata olives and crumbled feta cheese over the chicken and vegetables.
6. Roast in Oven: Place the sheet pan in the preheated oven and roast for 25-30 minutes until the chicken is cooked through and reaches an internal temperature of 165°F (75°C).
7. Broil for Crispness: For an additional 2-3 minutes, switch to broil to give the chicken a little crispiness, watching closely to avoid burning.
8. Rest and Garnish: Remove the pan from the oven and let it rest for 5-10 minutes. Garnish with fresh parsley before serving.
9. Serve: Serve warm, straight from the pan, ensuring everyone gets a bite of chicken, vegetables, and feta.

These steps will guide you in preparing an incredible Greek Chicken Sheet Pan Dinner that will undoubtedly become a household favorite.