Set instant pot to "saute". Once it reads "hot" add 1 tsp olive oil then break beef into large chunks and add to instant pot along with garlic and a few pinches of salt.
Let beef brown, stirring and breaking up beef occasionally, until cooked through, about 6 minutes. Press the "cancel" button to turn instant pot off.
Break spaghetti noodles in half. Add about 1/6 into an even layer over beef, then add another 1/6 going the opposite direction into an even layer. Repeat this pattern with remaining noodles four times (this doesn't need to be perfect! It's just to reduce sticking).
Add in marinara sauce, basil, tomatoes and water and season lightly with salt and pepper (don't stir).
Seal the lid of the Instant Pot, making sure the valve is set to "sealing." Press the "manual mode" button (or high pressure on other pressure cookers) and set to 7 minutes.
Once time is up, use the quick release method according to manufactures instructions (basically just stand back and flick the valve). Once sputtering stops open lid, remove basil and toss spaghetti with a fork.
Let rest two minutes (this will allow some of that extra liquid to soak in and the noodles to cook through). Sere warm with parmesan and basil leaves or chopped basil ribbons.
*Use spaghetti that lists 9 - 11 minutes to al dente.Parmesan cheese not listed in nutritional info.