Grease a 9x13-inch baking dish or spray it with nonstick cooking spray to ensure easy cleanup after baking.
In the prepared dish, combine diced chicken with lemon juice, olive oil, and all herbs and spices listed above. Allow it to marinate at room temperature for about 30 minutes while you preheat your oven to 375°F.
After marinating, add uncooked rice, grated zucchini, and chicken broth to the pan with marinated chicken. Stir everything together well until combined evenly.
Cover your dish tightly with foil and place it in the preheated oven to bake for approximately 40 minutes or until the rice is tender and most of the liquid has been absorbed.
Once done baking, fluff the rice gently with a fork, taste for seasoning adjustments if necessary, then serve topped generously with tzatziki sauce, fresh herbs, and a squeeze of lemon juice on top for added brightness.