Step 1

Preheat broiler.

Step 2

Arrange peppers on a baking sheet coated with cooking spray. Broil 6 minutes or until blackened in spots, turning occasionally.

Step 3

Remove lid from a 6-quart Instant Pot. Press [Sauté]; use [Adjust] to select “More” mode. When the word “Hot” appears, coat inner pot with cooking spray. Add beef; cook 5 minutes, turning to 1⁄4 teaspoon grated whole nutmeg

Step 4

Add peppers to pot; stir in, vinegar and next 3 ingredients. Stir in 1⁄4 teaspoon of the salt, black pepper, and chopped pepperoncini. Return beef to pot.

Step 5

Close and lock the lid of the Instant Pot. Turn the steam release handle to “Venting” position. Press [Slow Cook], and use [Adjust] to select “Less” mode. Press [-] or [+] to choose 8 hours cook time.

Step 6

When time is up, remove beef from cooker; shred with 2 forks. Stir beef and remaining 1⁄4 teaspoon salt into cooking liquid. Divide beef mixture evenly among hamburger buns, using a slotted spoon. Serve any extra sauce for dipping.