Ganache: Place chocolate chips in a metal mixing bowl. Bring cream to a simmer over medium heat. Pour simmering cream over chips and stir until melted. Set aside and allow to cool to room temperature.
Filling: Beat cream cheese and sugar with a handheld electric mixer until smooth. Scrape bowl with a spatula and mix in 1/3 cup heavy cream. Add the melted white chocolate, zest, and nuts and stir just until incorporated. Fold in the whipped cream. Spread into pre-baked pie shell and level off using a rubber spatula. Put in freezer until frozen.
To finish pie, place the ganache in the microwave on low for no more than 10 seconds at a time. Stir after each warming, until ganache pours loosely but is not even close to boiling. Be very careful when warming chocolate, as it will burn very quickly when heated in the microwave. Once chocolate is scorched it is unusable. Spread warm ganache over top of frozen pie, smoothing to the edges with a spatula.
Garnish: Beat cream and confectioners' sugar with a handheld electric mixer to stiff peaks. Transfer to a piping bag and pipe edges of pie with whipped cream. Sprinkle macadamia nuts over top. Refrigerate until ready to serve.