Prep the zucchini: Slice zucchini into half-moons. Toss with 1 teaspoon salt in a colander and let sit 15–20 minutes to draw out moisture. Pat dry thoroughly with paper towels.

Preheat the oven: Set to 400°F (200°C). Lightly grease a 9x13-inch baking dish.

Sear the chicken: Heat 1 tablespoon olive oil in a large skillet over medium-high. Season chicken with 1/2 teaspoon salt, pepper, smoked paprika, and half the Italian seasoning. Sear 4–5 minutes, stirring once or twice, until lightly browned but not fully cooked. Transfer to a plate.

Cook the veggies: Add remaining 1 tablespoon oil to the same skillet. Add onion and cook 3 minutes until softened. Stir in garlic for 30 seconds. Add the patted-dry zucchini and cook 4–6 minutes until it releases moisture and begins to brown. Season with a pinch of salt, pepper, the remaining Italian seasoning, and red pepper flakes if using.

Make the sauce: In a bowl, whisk Greek yogurt, chicken broth, eggs, 1/2 cup mozzarella, and Parmesan until smooth. Taste and season with a little salt and pepper. The mixture should be pourable but creamy.

Assemble the bake: Add the browned chicken to the zucchini-onion mixture and toss. Spread in the prepared baking dish. Pour the yogurt-egg sauce over the top and gently stir to distribute. Sprinkle the remaining 1/2 cup mozzarella evenly over everything.

Bake: Place in the oven and bake 22–28 minutes, until the center is set and the top is lightly golden. If you want extra color, broil for 1–2 minutes at the end, watching closely.

Rest and serve: Let the bake rest 5–10 minutes so it firms up. Garnish with chopped parsley or basil. Slice and serve warm.