Preheat your oven to 350°F (175°C) to ensure even baking.
Place the 19-inch pastry pie shell in your pie plate and prepare according to package instructions or your own recipe.
In a microwave-safe bowl, combine the semisweet chocolate chips and microwave in 30-second intervals until melted and smooth. Set aside to cool slightly.
Prepare the dark chocolate pudding according to package instructions and fold in the melted chocolate until well combined.
Gently fold in the shredded coconut and chopped nuts into the chocolate mixture.
In a separate bowl, beat the egg whites with cream of tartar until soft peaks form, then gradually add sugar until stiff peaks form.
Carefully fold the whipped egg whites into the chocolate mixture.
Pour the chocolate filling into the prepared pie shell, smoothing the top with a spatula.
Bake in the preheated oven for 25-30 minutes or until the filling is set but slightly jiggly in the center.
Once cooled, spread the whipped cream topping evenly over the pie and garnish as desired.
Refrigerate for at least 2 hours before serving to allow flavors to meld.