Heat a large skillet over medium heat and sauté sliced mushrooms until golden brown and reduced in size, allowing them to release and evaporate excess moisture.

Add spinach to the skillet and cook until wilted, stirring occasionally. Remove from heat and set aside.

In a large mixing bowl, combine softened cream cheese, chicken broth, garlic, onion powder, Italian seasoning, salt, and pepper, stirring until the mixture becomes smooth and creamy.

Add the cooked chicken, sautéed mushrooms, and wilted spinach into the bowl, then fold everything together until fully coated in the creamy sauce.

Stir in half of the shredded mozzarella cheese, leaving the rest for the topping.

Transfer the entire mixture into a baking dish and spread it evenly using a spatula.

Sprinkle the remaining cheese over the top and bake at 375°F (190°C) for 20–25 minutes, or until the top is melted, bubbly, and lightly golden.

Allow the bake to rest for 5 minutes before serving so the sauce thickens and flavors deepen.