Make crust: Grease a 6 inch springform pan with cooking spray. In a medium bowl, combine 1 1/2 cups crushed Oreos, melted butter, and a pinch of salt until mixture is the texture of wet sand.
Press mixture into bottom and up the side of the pan. Freeze for 20 minutes.
Meanwhile, make cheesecake: In a large bowl using a hand mixer, beat cream cheese, sugars, and sour cream until light and fluffy. Add eggs, one at time, and beat until just blended. Add vanilla, salt, and flour and beat until combined. Fold in remaining crushed Oreos. Pour batter on top of crust. Tightly wrap entire pan in two layers of foil.
Pour water into Instant Pot and place trivet in the bottom. Put springform pan on top. Secure lid and set to Pressure Cook on High for 37 minutes. Let pressure naturally release for 10 minutes, then follow manufacturer’s guide for quick release, making sure to wait until cycle is complete before unlocking and removing lid.
Remove cheesecake from the pot, unwrap and discard foil, then place on a wire rack to cool for at least an hour. Refrigerate for 4 hours or overnight.
Garnish with Cool Whip, more Oreos, and chocolate syrup.