Preheat the oven to 375°F (190°C).

In a large skillet, heat a drizzle of olive oil over medium heat. Add diced onions and minced garlic, sautéing for about 3-4 minutes until translucent.

Add bite-sized pieces of chicken to the skillet and cook for 6-8 minutes until browned and cooked through.

Stir in sliced zucchini and your choice of seasonings, cooking for an additional 3-4 minutes.

Transfer the chicken and zucchini mixture into a large bowl. Add beaten eggs and half of the mozzarella cheese, stirring to combine.

Pour the mixture into a greased baking dish, then top with breadcrumbs and the remaining cheese.

Bake for 25-30 minutes, watching for a golden-brown crust and bubbling edges.

Allow the casserole to cool for 5-10 minutes before serving.