Heat olive oil in a large skillet over medium-high heat. Season beef chuck roast with salt and pepper. Cook roast in hot oil until browned entirely, 2 to 3 minutes per side; transfer browned roast to a slow cooker.
Sprinkle onion, chile pepper, hot sauce, taco seasoning, chili powder, cayenne pepper, and garlic powder over the roast.
Cook on Low until meat is fall-apart tender, 8 to 10 hours.