Unfold piecrust, and place on a lightly floured surface. Roll out to 1/8-inch thickness. Carefully place piecrust in a 9-inch pieplate. Fold edges under, and crimp.
Bake on lowest oven rack at 400° for 8 minutes. Cool.
Sauté chicken and next 6 ingredients in a skillet coated with cooking spray over medium-high heat 5 minutes. Spoon mixture into prepared crust. Sprinkle with cheese.
Whisk together half-and-half, eggs, and 1/4 teaspoon pepper. Pour over chicken mixture.
Bake at 400° on lowest oven rack for 45 minutes or until set. Let stand 10 minutes.