Melt butter in large saucepan. Stir in flour and cook until bubbly. Slowly stir in chicken broth. Heat to boiling, stirring constantly, until sauce thickens. Reduce heat to low. Stir in milk, chicken and peas; heat until hot. Pour into 9-inch deep-dish pie pan.
Top with pie crust; seal edge and flute. Cut slits in several places in crust. Brush pastry with a little milk and sprinkle with pepper.
Bake 20 to 25 minutes or until crust is golden brown.