Pour the olive oil into your Instant Pot and add the meatballs in a single, even layer on the bottom. This helps them cook evenly and prevents sticking. Snap the spaghetti in half and arrange it directly over the meatballs in a crosshatch pattern—snapping it prevents the long strands from clumping together during cooking.
Pour the pasta sauce and water directly over the spaghetti and meatballs, stirring gently to distribute evenly and ensure the noodles are submerged. Sprinkle the garlic powder and Italian seasoning over the mixture—I like to season at this stage so the flavors infuse into the liquid as everything cooks together. The total liquid should cover the pasta by about an inch.
Seal the Instant Pot lid and set the valve to sealing position. Cook on high pressure for 10 minutes. The intense heat will cook the pasta perfectly while the meatballs stay tender, and everything will absorb the flavors of the sauce.
Once the timer beeps, carefully switch the valve to venting to quick-release all pressure. Remove the lid and stir the pasta and meatballs together gently, breaking up any clumps that may have formed. The pasta should be al dente and the sauce should coat everything evenly.
Transfer the pasta and meatballs to serving bowls or plates. Top generously with parmesan cheese and fresh basil if desired. The residual heat will help the cheese melt slightly into the sauce for a creamy finish.