Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast, zucchini, red bell pepper, and red onion into uniform bite-sized pieces.
Place the chicken and chopped vegetables onto the prepared sheet pan.
Drizzle the olive oil over the mixture and sprinkle evenly with dried oregano, garlic powder, sea salt, and black pepper.
Toss everything together with your hands or tongs until well coated, then spread into a single layer.
Roast in the center of the oven for 18 to 20 minutes, or until the chicken is cooked through and the vegetables are slightly caramelized.
Remove the pan from the oven and stir in the chickpeas and cooked quinoa, allowing them to warm through from the residual heat.
Transfer the mixture to a serving bowl and garnish with crumbled feta cheese, kalamata olives, and a fresh squeeze of lemon juice.