Preheat your air fryer to 350°F (175°C) for 3-5 minutes.

In a large bowl, combine the cream of mushroom soup, heavy cream, chicken broth, garlic powder, onion powder, thyme, salt, and pepper. Whisk until smooth.

Stir in the cooked chicken, spaghetti, and mushrooms (if using), mixing until well coated in the sauce.

Transfer the mixture into an air fryer-safe baking dish.

Evenly sprinkle the mozzarella and Parmesan cheese over the top.

If desired, add breadcrumbs over the cheese and lightly spray with olive oil for a crispy finish.

Place the dish in the air fryer basket and cook for 15-20 minutes, or until the top is golden and bubbly.

Check halfway through and rotate the dish if necessary to ensure even cooking.

Let the tetrazzini rest for 5 minutes before serving, and garnish with fresh parsley if desired.