Turn your Instant Pot to the saute setting. (See your manufacturer's guide for detailed instructions on how to use your instant pot.)
Add the butter and cook until the butter has melted. Add the garlic and ginger and saute for another minute or until the garlic becomes aromatic. Do not cook too long because you don't want to burn it.
Add the tomato puree and tomato paste to the Instant Pot and stir. Add the garam masala, coriander, cumin, paprika, turmeric and salt to the Instant Pot, stir and cook for about 3 to 5 minutes.
Add the chicken thighs, water and stir everything together. There should be enough liquid in the pot to cover the chicken, so add more water if needed.
Close the lid (follow the manufacturer's guide for instructions on how to close the instant pot lid). Set the Instant Pot to the Poultry setting and set the timer to 5 minutes.
Once the Instant Pot cycle is complete, wait until the natural release cycle is complete, should take about 10 minutes. Follow the manufacturer's guide for quick release, if in a rush. Carefully unlock and remove the lid from the instant pot.
Switch the Instant Pot to the saute setting (do not put the lid on). Add the whipping cream and simmer for 5 minutes, stirring occasionally. The sauce should thicken and reduce a bit. You don't want it to reduce too much.
Turn off the Instant Pot and garnish with fresh parsley. Serve warm over rice and with naan.