Heat pecans, butter and brown sugar in small saucepan until butter and sugar are melted and mixture comes to a boil. Boil exactly 30 seconds. Spread on bottom of pastry shell. Cool.
Beat whipped topping mix, 1 cup of the milk and vanilla in large bowl with electric mixer on high speed about 6 minutes or until topping thickens and forms peaks. Add remaining 1.75 milk and pudding mixes; blend on low speed. Beat on high speed 2 minutes, scraping bowl occasionally. Stir in 1 cup of the coconut. Spoon into pastry shell.
Refrigerate at least 4 hours or until set. Garnish with remaining one third coconut. Store leftover pie in refrigerator. Makes 8 servings.