Cut off any fat around the chuck roast that you can. It's OK if there is fat marbled throughout the roast. Just cut off any from the sides that you can.
Add the meat to the crock pot along with the peperoncini juice and a few peppers, Italian seasoning, garlic powder, and sprinkle on some salt and pepper.
Cook on low for 8 hours.
Shred the meat in the crock pot, it should be very tender and cooked through.
Serve on Kaiser buns or hamburger buns with a few more peppers on top.