Preheat oven to 350. Lightly grease a 3 quart baking dish.

In a large skillet, melt butter over medium heat. ADd green onion and prosciutto; cook 5 to 6 minutes, stirring occassionally or until prosciutto is crispy. Add broccoli and chicken broth; cook 5 minutes, stirring frequently. Remove from heat. Stir in chivcken, soup, sour cream, cheese, mustard, and pepper. Add noodles, tossing gently to coat. Spoon into prepared baking dishes.

In a small bowl, combine panko & melted butter; sprinkle evenly over casserole.

Bake 30 minutes.