Season the beef chuck roast with salt, black pepper, garlic powder, and onion powder on all sides.
Place the seasoned roast in the slow cooker and pour the beef broth and Worcestershire sauce over it.
Cover and cook on low for 8 hours or on high for 4 hours, until the beef is tender and easily shredded.
Once cooked, remove the roast from the slow cooker and shred it using two forks. Return the shredded beef to the slow cooker and stir to combine with the juices.
To assemble the sandwiches, place a generous portion of the shredded beef on the bottom half of each sandwich roll. Top with slices of cheddar cheese.
Cover with the top half of the rolls and place the sandwiches under the broiler for 2-3 minutes, or until the cheese is melted and bubbly.
Serve immediately, adding sliced jalapeños if desired.
