In a small bowl, whisk together beef broth, mustard, red wine vinegar, tomato sauce, Worcestershire sauce, and soy sauce.
Season beef roast with garlic powder, salt and pepper on all sides.
Add butter and oil to your instant pot and place on sear setting. Sear beef roast on all sides for about 30 seconds on each side. When done, pour sauce over beef.
Set your instant pot to cook on “high” or “manual” mode for 1 ½ hours. Let pressure release naturally when done (about 15 minutes). When done, shred beef with two forks.
Serve shredded beef on buns, tortillas, or on its own with your favorite side dishes.