Once the onions are soft, nestle the beef roast into the bottom of the pot (You may need to cut into large chunks if roast is too big.
Add the pepperoncinis, pepper juice, Worcestershire sauce, beef broth, keto-friendly sweetener, Italian seasoning, and salt, over the beef. Stir gently to mix the seasonings and liquids.
Secure the Instant Pot lid and ensure the valve is set to sealing. Choose the Pressure Cook High setting and set the timer for 60 minutes.
Once cooking is complete, allow a Quick Release of pressure by switching the valve. When the pressure has released, carefully remove the lid.
Using tongs or two forks, shred the beef into the flavorful juices in the pot. Give it a quick stir to fully combine. Taste and adjust the seasoning with additional salt or pepper if needed.