Place butternut squash, onion, ginger, garlic, salt, pepper, turmeric, nutmeg and coconut milk in an Instant Pot or an electric pressure cooker.
Set the Instant Pot at High pressure for 8 minutes. When cook time is complete, let pot release pressure naturally for 10 minutes. Then release any remaining pressure.
Open the lid and carefully. Use an immersion blender to blend the sauce until smooth, adding a little water to get the soup to your desired consistency.
Garnish with a little extra grated nutmeg, if desired.
Don't get too hung up on exactly how to measure a tablespoon of garlic or ginger. Just throw some in that's approximately right, and you'll be good to go.
If you're not comfortable with this casual way of measuring, then use 1 tablespoon each of minced garlic and ginger.
This soup serves 4 when used as a side dish. If all you are having is soup it may only serve 2--or maybe one if you're super hungry.