In a large mixing bowl, combine the pudding mix with the Cool Whip until smooth and creamy.
Gently fold in the sliced peaches, mini marshmallows, shredded coconut, and chopped pecans if using.
Stir until all ingredients are well coated in the creamy mixture.
Refrigerate for at least 1 hour before serving to let the flavors blend.
Serve chilled and enjoy!