In a mixing bowl, beat cream cheese and powdered sugar until smooth. Spread over the bottom of the graham cracker crust. Sprinkle with the 1/4 cup pecans. In another bowl, combine the pudding mixes with the cold milk and vanilla. Beat on low speed for one to two minutes until it starts to thicken. Spoon over the pecans in the pie pan. Chill for at least two hours or overnight. Top with whipped cream and the 3/4 cup pecans.