In a mixing bowl, combine vanilla wafer crumbs, granulated sugar, and salt. Pour in melted unsalted butter and mix until evenly moistened. Firmly press into the bottom of a springform or cheesecake pan lined with parchment. Chill for 30 minutes.

Using an electric mixer, beat room temperature cream cheese until smooth and creamy, about 2-3 minutes. Gradually add instant pistachio pudding mix, vanilla extract, and powdered sugar, mixing until combined. Pour in heavy cream and whip until fluffy. Spoon filling into the chilled crust, smoothing the top.

Cover cheesecake with plastic wrap and refrigerate for at least 6 hours, preferably overnight, to allow it to firm up and flavors to meld.

In a clean mixing bowl, whip heavy cream, powdered sugar, and vanilla extract until stiff peaks form, about 3-5 minutes. Spread or pipe whipped cream over cooled cheesecake.

Sprinkle chopped pistachios over the whipped cream before serving. Serve chilled.