Pour chicken broth into pot, then place potatoes into pot directly in the broth. Set the trivet on top of potatoes, then carefully place roast on trivet.
Close and lock the lid of the Instant Pot. Press “Manual” and immediately adjust the timer to 30 minutes.
Check that the cooking pressure is on “high” and that the release valve is set to “Sealing.”
When time is up, open the IP using “Quick Pressure Release.” Remove the roast and trivet from the pot, leaving behind the potatoes and broth. Set roast on cutting or carving board to rest while you mash the potatoes. Add blue cheese and stir to combine.
Season with salt and pepper, then slice roast and serve.