Turn the Instant Pot on to "saute" mode - press the "saute" button until it light indicates "high" or "more." Add the ghee and while it melts, chop up the potato, onion and red pepper. Add the potatoes to the IP and saute until browned, stirring occasionally for about 10 minutes, then add the onion and red pepper. Stir in the garlic and ginger. Saute until softened, about 5 minutes. Season with salt and pepper, to taste.
Add the canned tomato to the IP. Stir all the spices and pastes into the vegetable mixture. Heat until fragrant, about 2-3 minutes, then add the chunks of chicken. Let the chicken brown on one side, as desired, or skip to the next step.
Pour in the chicken broth. Add more paprika or turmeric to achieve the color you want, as desired (I added more paprika for a reddish korma). Season with salt and pepper. Bring to a rolling bubble on "saute" mode.
When the oils begin to separate, after about 5 minutes of bubbling, cancel the "saute" mode. Secure the lid on the IP. Press the "Pressure Cook" button so it is on the "high" or "more" setting. Turn the valve to "sealing." Set the timer to 7 minutes. Let the IP pressurize. Cook the naan and basmanti rice, if serving, while the IP pressurizes over about fifteen minutes.
Let the IP depressurize naturally or do a VERY CAREFUL quick release by adjusting the valve from "sealing" to "venting" - be sure to wear an oven mitt or similar heat protection!!
Remove the IP lid. Spoon about a half cup of the korma mixture into a bowl with the Greek yogurt and stir well to combine. Don't add the yogurt directly to the IP or else it may curdle and separate. It's okay if it does this, but it creates a thicker korma if it doesn't! Simmer the korma on saute mode to thicken up, as needed. Serve the korma hot. Garnish with cilantro or parsley, serve alongside a bed of basmantic and several stacks of naan. Enjoy!