In the Instant Pot inner pot, place the sausage, onions , Italian seasoning, garlic powder, salt and pepper and and press SAUTE on the IP.
Saute the mixture until it’s cooked through and the onions are tender.
Add the spaghetti sauce, water/broth, and dry spaghetti noodles.
Mix every well (make sure all noodles are covered in liquid) and place the lid on the Instant Pot, and bringing the toggle switch into the “seal” position.
Press MANUAL or PRESSURE COOK and adjust time for 5 minutes.
When the five minutes are up, do a natural release for 5 minutes and then move the toggle switch to “Vent” to release the rest of the pressure in the pot.
Remove the lid. If the mixture looks watery, press “Saute”, and bring the mixture up to a boil and let it boil for a few minutes. It will thicken as it boils. Add the spinach to the pot, stir and let warm through for a few minutes.