For the crust: In a medium bowl, combine graham cracker crumbs and sugar. Stir in melted butter until well combined. Press mixture firmly into the bottom and up the sides of a 9-inch pie plate.
For the filling: In a large bowl, whisk together instant chocolate pudding mix and milk until smooth and thickened. Gently fold in the thawed whipped topping until just combined.
Spoon the chocolate filling into the prepared pie crust.
For the topping: In a medium saucepan, melt butter over medium heat. Stir in brown sugar and evaporated milk. Bring to a boil, stirring constantly. Cook for 1 minute. Remove from heat and stir in coconut and pecans.
Spoon the coconut-pecan topping evenly over the chocolate filling.
Refrigerate for at least 4 hours, or until firm, before serving.
Notes
This pie is best served chilled. You can prepare the topping a day in advance and store it in an airtight container at room temperature.