In a large pot over medium heat, add the butter. Once the butter has melted, add the prepared chicken and cook until golden brown on each side and reaches an internal temperature of 160�. Remove the pot and transfer to a cutting board. Allow to rest for 5 minutes.
Add the mushrooms, onion, celery and carrots, saute until tender, about 5-7 minutes. Add the garlic and cook until fragrant. Pour in the chicken stock along with the half and half, whisk, scraping up any browned bits from the bottom of the pan. Turn the heat up to medium-high and bring the mixture to a boil.
Cut the chicken into small bite-size chunks and return it to the pot. Add the salt, pepper, garlic powder, thyme, sage, cayenne and paprika. When the mixture begins to boil, add the pasta and reduce heat to medium. Cook for 10-15 minutes, then add the corn, peas and parsley. Cook until the pasta is tender and the sauce is thick, about 6-8 minutes (note: the sauce with thicken as it cools). Remove from the heat and serve with pie crust crumbles, if desired.