Add the cubed butternut squash and chopped onion to a food processor and pulse until they are broken down into tiny pieces that are no larger than a grain of rice. You may need to scrape the sides of the food processor bowl to make sure all the butternut squash and onion get chopped.
Turn the Instant Pot on 'Sauté' and using the 'Adjust' button, adjust the heat level to 'Normal' and allow it to warm up for a few minutes until the pot reads 'Hot'.
Add the butter to the Instant Pot and allow it to melt. To help the butter melt more quickly and evenly, use a spoon or spatula to continually move it around the bottom of the hot liner until it has fully melted.
As soon as the butter has melted, add the butternut squash and onion from the food processor to the Instant Pot. Sauté them in the butter for 4 to 5 minutes, tossing periodically until the squash begins to get soft. Do not allow the squash to start browning.
mix in the Spices, Stock & Pasta
Add the cinnamon and nutmeg to the pot and mix into the squash and onion. Allow the spices to cook into the vegetables for a minute or two to give them a chance to release their wonderful flavors and aromas. Keep a close eye and be careful not to let the spices start burning to the bottom of the liner.
Turn off the 'Sauté' function and then add the chicken stock and salt to the pot. Mix all the ingredients together, deglazing the liner to remove anything that may have gotten stuck to the bottom during cooking.
Add the pasta to the pot and give everything a gentle stir.
set the Cook Time
Set the Instant Pot to cook on "Manual" / "Pressure Cook", "High Pressure" for 2 minutes. Once cooking has completed, allow for a 2-minute NPR (Natural Pressure Release).
After the 2-minute NPR has completed, release any remaining pressure from the pot. Once all the pressure has been released, carefully open your pot.
add the Final Ingredients
Add the heavy whipping cream to the pasta and mix it in well. Then add the shredded cheese and mix until all the cheese melts into the pasta.