Preheat oven to 375°F (190°C)

Lightly grease a casserole dish

In a large bowl combine shredded chicken, broccoli, cauliflower, spinach, mushrooms, bell peppers, and zucchini

In a separate bowl mix cream cheese, heavy cream, and sour cream until smooth

Add chicken broth if you prefer a slightly thinner sauce

Stir in Dijon mustard if using

Season with garlic powder, onion powder, Italian herbs, salt, black pepper, and smoked paprika

Pour the creamy sauce over the chicken and vegetables

Mix until everything is evenly coated

Transfer the mixture into the prepared casserole dish

Sprinkle cheddar cheese, mozzarella, and parmesan evenly on top

Bake until the casserole is bubbly and the cheese is golden

Let the casserole rest slightly before serving