Allow the ice cream to soften for about 10 minutes at room temperature. You don't want it melted but easy to scoop and mix together.
Place the softened ice cream in a large mixing bowl and add 3/4 cup chopped macadamia nuts. Stir until well combined.
You will need a mixing bowl that is about 2 quarts and the rim can easily fit inside your pie crust. This is needed to create the dome shape of the pie.
Line the bowl with plastic wrap and make sure to allow enough overhang to easily remove from the bowl. I suggest spraying with nonstick cooking spray as well.
Spread the ice cream into the lined bowl. Cover with additional plastic wrap and freeze for 3-5 hours until the ice cream is firm.
Remove the top layer of plastic wrap from the bowl. Carefully pull the plastic wrap on the bottom to remove the entire dome of ice cream out of the bowl.
Place the flat side of ice cream in the crust.
Make sure the hot fudge sauce is room temperature but not heated. Spread on top of the ice cream. It is ok if it does not go all the way to the bottom as the whipped cream will cover the edges. This is easiest to do if you dump the entire cup of hot fudge sauce on top and quickly spread.
Place in the freezer for 40-60 minutes to allow the hot fudge to set.
When ready to serve, garnish the edges of the pie with whipped cream to resemble a hula skirt. This is easy to do by squirting vertical lines of Reddi-wip along the sides of the pie.
Sprinkle the remaining 1/4 cup chopped Macadamia nuts on top.
Then the pie is ready to slice, serve and enjoy!