Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).
In a 9x13 inch baking dish or on a large rimmed sheet pan, combine the cubed chicken, zucchini, cherry tomatoes, bell pepper, and red onion.
Drizzle the olive oil over the chicken and vegetables.
Sprinkle with dried oregano, garlic powder, sea salt, and black pepper.
Toss all ingredients together until evenly coated and spread into a single layer.
Bake in the preheated oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165 degrees Fahrenheit and the zucchini is tender-crisp.
Remove from the oven, drizzle with fresh lemon juice, and garnish with crumbled feta cheese and chopped parsley before serving.