Use a sharp knife to carefully cut the spaghetti squash in half lengthwise. Scrape out the seeds with a spoon and discard.
Place 1 cup water and trivet into the pressure cooker or Instant Pot. Place spaghetti squash on the trivet, close and secure the lid. Cook on High Pressure for 15 minutes, carefully performing a quick release at the end of the cook time.
Carefully transfer spaghetti squash to a cutting board. Use a fork to gently pull the spaghetti strands of flesh away from the skin.
Season to taste with salt, pepper and a drizzle of oil, if desired. You can slo serve the squash with pasta sauce, Parmesan cheese or parsley and basil.
Nutritional information does not include pasta sauce, cheese or additional toppings.