Grease a 7 inch springform pan, set aside.
Prepare cheesecake batter by placing cream cheese, sugar, sour cream, and flour in a medium sized bowl. Use a hand mixer and beat on medium speed until smooth. Then add your egg and vanilla and continue beating until blended. Set aside.
Prepare cake batter by placing vegetable oil and sugar in a separate medium bowl. Use a hand mixer and beat on medium speed until blended. Add flour, baking soda, cinnamon, nutmeg, and salt, egg, and vanilla extract. Beat on medium speed until well blended. Add carrots, pineapple, and walnuts to bowl and fold into batter by mixing with a spatula.
Pour about half of the the carrot cake mixture into the bottom of your greased springform pan, spreading it out so it covers the bottom of the pan. Then add cream cheese batter in the middle of the carrot cake batter. Lightly spread the cream cheese mixture over the cake mixture. Repeat these steps until all batter is in the springform pan, finishing with cream cheese layer on top.
Cover springform pan with foil paper.
Add 1 cup of water to Instant Pot. Add cake to Instant Pot on trivet or bakeware sling.
Cook on high pressure for 35 minutes, allow to natural release for 10 minutes.
Remove cake and allow to cool on counter, then transfer to fridge. Refrigerate 2-24 hours, the longer the better. Enjoy :)