Add the oil to the insert of the Instant Pot. Press Saute function (ensure temp is set to normal). Add the onions and cook, while stirring, until they start to soften and become translucent. Add the garlic and ginger and cook for 15 seconds.
Add the chicken and cook, stirring often, 1-2 minutes.
Stir in the potatoes, spices (coriander, garam masala, turmeric, salt and paprika), tomato sauce, and coconut milk.
Lock the lid and make sure the valve is set to closed. Select the Manual or Pressure Cook button and set to 7 minutes.
After the cooking time is finished, quick release the pressure and remove the lid.
Add the butter and stir. Serve over rice garnished with fresh cilantro, if desired.