Follow these straightforward steps to create your easy Chicken Tetrazzini:

1. Preheat Oven: Preheat your oven to 350°F (175°C) to ensure it’s ready for baking.
2. Cook Noodles: In a large pot of salted boiling water, cook the egg noodles according to package instructions until al dente. Drain and set aside.
3. Sauté Vegetables: In a large skillet over medium heat, add the olive oil. Sauté the mushrooms until they are tender, about 5 minutes.
4. Combine Ingredients: In a large bowl, combine the cooked chicken, sautéed mushrooms, frozen peas, chicken broth, heavy cream, garlic powder, onion powder, dried parsley, salt, and pepper.
5. Fold in Noodles: Add the cooked egg noodles to the chicken mixture and gently fold until well combined.
6. Transfer to Baking Dish: Pour the mixture into a greased 9×13 inch baking dish. Top with shredded cheddar and mozzarella cheese, then sprinkle with grated Parmesan.
7. Bake: Bake in the preheated oven for 25-30 minutes, or until the cheese is melted and bubbling. Allow the dish to cool for 10 minutes before serving.

Now you have a deliciously creamy and cheesy Chicken Tetrazzini ready to wow your guests!