Pat the pork dry. This helps the seasoning stick and gives the roast a better sear.
Season the pork. Mix the salt, paprika, garlic powder, black pepper, thyme, and rosemary, then rub it evenly over the roast.
Sear the pork. Set the Instant Pot to Sauté, add olive oil, and brown the pork on several sides. Remove it once the outside has good color.
Deglaze the pot. Turn off Sauté and pour in the broth. Scrape the browned bits from the bottom with a wooden or silicone spoon.
Add the flavor. Stir in Worcestershire sauce and Dijon mustard.
Add the vegetables. Put the onion, garlic, potatoes, and carrots into the cooking liquid. Keep the potato and carrot pieces fairly large so they hold their shape.
Return the pork. Place the seared pork loin back into the Instant Pot, sitting among the vegetables.
Pressure cook. Secure the lid and set the valve to Sealing. Cook on High Pressure for about 18 minutes for a 2–2½-pound roast.
Let the pressure release naturally. Allow 10 minutes of natural release, then carefully release any remaining pressure.
Check the pork. Insert an instant-read thermometer into the thickest part. Pork should reach 145°F (63°C), followed by at least 3 minutes of rest.
Rest before slicing. Transfer the pork to a cutting board and let it rest before cutting. This helps keep the slices juicy.
Make the sauce. If you want a thicker sauce, combine cornstarch and cold water. Turn the Instant Pot to Sauté and stir the mixture into the cooking liquid until slightly thickened.
Slice and serve. Cut the pork into slices and serve it with the potatoes, carrots, and warm pan sauce.