Make cheesecake filling: In a large bowl using a hand mixer or in a stand mixer fitted with the whisk attachment, beat cream cheese until fluffy and no clumps remain.
Add sugar and beat until combined. Add heavy cream and vanilla and beat until medium-stiff peaks form. Set aside.
In a medium bowl, whisk together pudding mix and milk. Let pudding stand for 3 minutes in the fridge until thickened. Fold into cheesecake mixture until combined.
Pour half the filling into graham cracker crust. Add a single layer of sliced bananas and Nilla Wafers (20 total), then pour over remaining cheesecake mixture and smooth top.
Refrigerate until cheesecake is firm, at least 6 hours and up to overnight. (If the cheesecake stills feels too soft to slice, transfer to the freezer for up to 1 hour.)
Before serving, top with dollops of whipped topping around the border of the cheesecake. Top each dollop with a banana slice and Nilla wafer, then garnish the whole cheesecake with crushed Nilla Wafers.