Dry the roast with a paper towel and sprinkle it with salt and pepper.
Select the sauté button on the Instant Pot. Add the oil to the cooker and allow to warm.
Add the roast and brown all sides of it. This process takes about 7-10 minutes. Remove the roast from the cooker
Next add the onions and garlic to the cooker. Continuously stir while cooking until just softened, about 5 minutes. Once done, press Cancel.
Pour in half the beef broth and deglaze the bottom of the Instant Pot by scraping the bottom with a wooden spoon or spatula to prevent getting the “Burn” message.
Add the roast, peppers, remaining beef broth, butter and ranch dressing to the onions in the cooker. Place the lid of the Instant Pot on and turn the steam gauge to the Sealing position.
Select Manual or Pressure Cook button and set the time to 55 minutes. It will take about 10 minutes to come up to pressure before the timer will start.
Cook until the timer goes off and allow the pressure to release naturally. This will take about 10 minutes.
Remove lid and remove the roast. Add the chives, dill and the pepperoncini juice and stir.
Add the roast back in to the Instant Pot and using a fork, shred the beef into large chunks. Stir it into the juices and serve over mashed potatoes or egg noodles.