Season pork with salt and pepper. Set your Instant Pot to sauté on Normal. When the display says Hot, add oil and heat until shimmering. Add pork and cook, turning often, for 5 minutes or until browned on all sides. Using tongs, transfer pork to a plate.
Carefully add vinegar to the pot and cook, scraping up any browned bits from the bottom of the pot, for 1 minute. Press Cancel. Add broth, maple syrup and mustard, stirring well. Return pork and any accumulated juices to the pot.
Close and lock the lid and turn the steam release handle to Sealing. Set your Instant Pot to pressure cook on Low for 2 minutes.
When the cooking time is done, press Cancel and let stand, covered, for 5 minutes, then turn the steam release handle to Venting. When the float valve drops down, remove the lid. An instant-read thermometer inserted in the thickest part of a tenderloin piece should register at least 145°F (63°C) for medium-rare to medium. (If more cooking time is needed, continue pressure cooking on Low for 2 minutes, then quickly release the pressure.) Using tongs, transfer pork to a cutting board, tent with foil and let rest until sauce is finished.
Set your Instant Pot to sauté on Less. Add butter and cook, stirring often, for 2 minutes or until butter is melted and combined.
Slice pork across the grain into medallions. Serve drizzled with maple mustard sauce.