Salt and pepper the chuck roast on each side. Heat the olive oil in a skillet, and brown the roast on each side. Place the roast in a slowcooker and top with the onion, green chiles, chili powder, garlic powder, and hot sauce. Pour in enough water to cover 1/3 of the roast and toss in the beef bouillon cube.
Cover and cook on high for 6 hours, checking to be sure there is always at least a small amount of liquid in the bottom. Reduce heat to low and continue cooking for another 2 hours.
Shred the meat, and let it cool. Taste it, and add more hot sauce if you want it spicier. I like mine plenty spicy. I refrigerate mine overnight and assemble the tamales the next day.
Soak the corn husks in a large container full of warm water and allow to soak for 3 hours.