Place choc chips in metal mixing bowl. Bring cream to a simmer over medium heat. por simmering cream over chips and stir until melted. Set aside let cool to room temperature.
Beat cream cheese and sugar until smoothe (with hand mixer). Scrape bowl and mix in 1/3 c heavy cream. Add melted white choc, zest, and nuts. stir until incorporated. Fold in the whipped cream. Spread into baked pie shell and level off using spatula. Put in freezer until frozen.
To finish pie, place ganache in microwave on low for no more than 10 sec at a time. Stir after each warming, until pours loosely (not too hot). spread ganache over frozen pie, smoothing to edges with spatula.
Beat cream and sugar with hand held mixer until stiff peaks form. Transfer to piping bag and pie edges of pie. Sprinkle with crushed mac nuts. Keep refrigerated until ready to serve.