Cut the chuck roast into 3 large pieces, and place in the bottom of the Instant Pot
Sprinkle about half of the onion soup mix and all of the garlic powder over the roast
Pour the beef broth and Worcesteshire sauce round the meat
Add the potatoes, carrots and celery on top of the roast. Sprinkle remaining soup mix over vegetables
Place the lid on the pressure cooker, make sure valve is set to sealing, and hit PRESSURE COOK for 60 minutes
Pot will take a few minutes to reach pressure, then begin counting down and cook. When pot beeps, allow a 15 to 20 minutes natural pressure release, then quick release remaining pressure
When pin drops, carefully remove lid. Roast should be tender and shreddable with fork. Remove to a platter to shred, and serve with vegetables
Optional gravy. In a small bowl, mix 2 tablespoons cornstarch with 2 tablespoons water until well combined. Hit saute, and when juices boil, stir in cornstarch slurry, and boil for about 5 minutes or until sauce thickens