Make one batch of white sauce, according to the Simple White Sauce recipe (above), and set aside.
In a medium pot, add vegetables. Add water just to cover. On medium-high heat, boil the vegetables for 8 minutes or until crisp tender. Remove from heat and drain.
Add the vegetables, cheese, and several pinches each of rosemary and parsley to the white sauce. (Hint: Crush the herbs in your hand to release added flavor)
Coat a deep casserole dish with nonstick cooking spray.
Gently stir chicken into white sauce, and pour mixture into the casserole dish.
Cover the mixture with the pre-made pie crust. Snip a few holes into the pie crust and crimp around the edges of the dish.
Bake at 350 degrees for 30 minutes or until the crust is browned.