Instant Pot Spaghetti

Set the Instant Pot to sauté. Add the olive oil to the inner pot, then add the onion and cook until it starts to turn translucent. Add the garlic, garlic salt, and Italian seasoning. Cook for 30 seconds.
Add the ground beef. Cook, breaking the meat up as you go, until it is completely browned. Turn off the sauté setting. Drain any excess grease if necessary (a tablespoon or two is fine and adds flavor).
Pour in a splash of the chicken broth and scrape the bottom of the pot with a wooden spoon until there are no stuck-on bits left.
Lay the spaghetti on top of the meat mixture, adding it in a few small batches and crisscrossing the directions. Pour the remaining chicken broth around the noodles, then add the marinara sauce and diced tomatoes right on top. Push the spaghetti down with a spoon so it is fully covered in liquid. Do not stir.
Lock the lid on and set the steam release knob to sealing. Set the Instant Pot to pressure cook (manual) for 8 minutes. Press start if your pot requires it. The pot will take several minutes to come to pressure, then the cook time will begin.
When the cook time finishes, turn off the Instant Pot and do a quick release by turning the steam release knob to venting.
Stir the spaghetti well and let it rest for 5 minutes to absorb the liquids. Serve immediately topped with Parmesan cheese as desired.