Heat instant pot and prepare roast: Turn on Instant pot to high saute mode and allow it to heat up. In a separate, small bowl, combine 1 teaspoon salt, 1 teaspoon onion powder, 1 teaspoon garlic powder, and 1/2 teaspoon black pepper. Pat the chuck roast dry with a paper towel. Rub the spice mixture over the entire roast.
Brown roast: Add 1 Tablespoon oil to heated instant pot and allow the oil to heat up for about 30 seconds to one minute. Add roast and cook for 3 minutes on each side, until seared well.
Prepare vegetables: Cut 1 1/2 pounds of baby potatoes in half (or leave whole). Cut onion in two large chunks. Cut the peeled 6 carrots into thirds.
Pressure cook roast and vegetables: Switch the setting on the instant pot to pressure cook. Add roast, 15 ounces beef broth and 2 Tablespoons Worcestershire sauce. Set the vegetables and rosemary around the roast. Sprinkle with salt and pepper to taste. Add 60 minutes to the Instant Pot, lock the lid and make sure the vent is closed.
Release steam: When roast is done cooking, allow the vent to do a natural release for 10 minutes.
Transfer roast and vegetables: Move roast and vegetables to a serving platter, leaving all liquid in the Instant Pot. Follow notes below for gravy instructions.
Notes
Gravy Instructions: After the roast and vegetables are removed from the instant pot, change the setting to soup and allow the liquid to boil. In a small bowl, whisk together 2 Tablespoons cornstarch and 1/4 cup water. Add to boiling broth and whisk until it thickens into gravy. Add salt and pepper, to taste.Baby Carrots: Baby carrots cook much faster than regular carrots, and tend to get mushy when overcooked. If you plan on using them, do not add them to the initial 60 minutes of cooking time. Cut the cooking time down by 5 minutes, and do a fast release of pressure. Add the carrots, close the lid and vent and pressure cook for an additional 5 minutes.