Yes, any hard squash can be cooked easily in the Instant Pot. If you use squash puree a lot, it’s very easy to cook the squash, peel and seed it, and then return the chunks to the same pot and use Saute to make your puree with an immersion blender - no non-stick coating to scratch up and just one pot.
How do you cook winter squash in one? Do you just stick it in there with a little water?
I’ve cooked my butternuts in a microwave, with some water and tenting with plastic wrap. It makes a humid mess.