Preheat oven to 450 degrees.

Cook vermicelli pasta according to package directions, omitting salt and fat.

Drain the pasta well.

In a large nonstick skillet, add onion powder, sherry, and presliced mushrooms.

Cover the skillet and cook until the mushrooms are tender, about 4 minutes.

Drain off approximately half of the liquid from the skillet.

In a large bowl, combine the peas, skim milk, fat-free sour cream, grated parmesan cheese, and reduced-fat cream of chicken soup.

Add salt, black pepper, cooked and chopped chicken, the cooked pasta, and the mushroom mixture to the soup mixture.

Gently toss all ingredients to combine thoroughly.

Spoon the mixture into a 13x9-inch baking dish that has been coated with cooking spray.

In a small cup, combine dry breadcrumbs and melted butter, tossing to combine.

Sprinkle the breadcrumb mixture evenly over the pasta mixture in the baking dish.

Bake at 450 degrees for about 12 minutes, or until the dish is bubbly and thoroughly heated.