Press the Instant Pot button to sauté. Let it heat up then add the ground beef. Add the Italian seasonings, salt, onion powder, and garlic powder. Cook the meat, breaking it up until no longer pink.
Turn off the sauté button. Break the spaghetti in half and place on top of meat in a criss-cross pattern in the Instant Pot (this helps prevent clumping).
Pour marinara sauce over spaghetti. Pour water over the mixture trying to make sure all the noodles get wet. Seal instant pot and set to pressure cook mode on high pressure for 8 minutes.
As soon as the time is up, use the quick release button. When pressure has released, open and stir the spaghetti. Serve immediately and serve with grated Parmesan.