Season the beef chuck roast generously with salt and pepper.
Set the Instant Pot to 'Sauté' mode. Add olive oil and brown the roast on both sides, about 3-4 minutes per side. Remove roast and set aside.
Add chopped onion and garlic to the pot and sauté for 2 minutes.
Stir in tomato paste and Worcestershire sauce. Cook for 1 minute.
Pour in beef broth and deglaze the bottom of the pot by scraping up browned bits.
Return the roast to the pot. Sprinkle thyme and rosemary on top.
Seal the Instant Pot and cook on high pressure for 60 minutes.
Let pressure release naturally for 10 minutes, then quick release any remaining pressure.
Add the potatoes and carrots to the pot. Seal again and cook on high pressure for 10 minutes.
Quick release pressure, remove roast and veggies. Optional: mix cornstarch slurry into the remaining liquid and sauté until thickened to make gravy.
Slice roast against the grain, serve with vegetables and gravy.