Start by pressing the "Sauté" button on your Instant Pot. Once hot, add the ground turkey or beef along with the kosher salt. Cook until browned, breaking it apart with your wooden spoon. This should take about 5-7 minutes.
Next, add the diced onion and minced garlic to the pot. Sauté for an additional 2-3 minutes, or until the onion is translucent and fragrant.
Pour in the 2 cups of water and the marinara sauce. Stir everything together, scraping the bottom of the pot to release any bits stuck on.
Now, add the spaghetti. Make sure to submerge the pasta in the sauce, but do not stir. This will help prevent the pasta from sticking together.
Secure the lid on your Instant Pot and set the valve to sealing. Select "Manual" or "Pressure Cook" and set the timer for 8 minutes.
Once the cooking time is up, carefully perform a quick release by turning the valve to venting. Allow the steam to escape before opening the lid.
Gently stir the spaghetti and sauce together. Serve hot with a sprinkle of grated parmesan cheese on top, if desired. Enjoy your homemade Instant Pot Spaghetti with Meat Sauce!