Turn Instant Pot on saute. Once the pot is hot, add the oil.
Add beef and season with salt and pepper. Saute beef until browned on all sides.
Move the beef over to half of the pot and add onions to the other half of the pot. Saute onions until tender.
Add garlic and stir.
Add tomatoes, mushrooms, beef broth, and gravy. Stir and close pressure cooking lid.
Cook on high pressure with valve set to "seal" for 20 minutes.
Once the timer beeps, let the pressure release naturally for 10 minutes and then quick release the remaining pressure. Open lid and stir.
Pour in noodles. Do not stir! Gently press the noodles down into the liquid.
When the timer beeps, naturally release pressure for 5 minutes and then quickly release remaining pressure.
Open lid and stir.