Add the red chile sauce, beef bouillon, 2 tablespoons chili powder, cumin, oregano, onion powder, garlic powder and black pepper to a 6- to 7-quart slow cooker and stir to mix. Add the chuck roast and turn to coat it in the sauce. For more consistent cooking time, avoid putting the beef into the slow cooker refrigerator-cold. Cover and cook on LOW until the beef pulls apart easily with a fork, about 7 hours for one large roast. Begin checking earlier if using two smaller roasts, since they can become tender sooner. If the beef is still firm or difficult to pull apart, continue cooking and check again every 30 minutes until it pulls apart easily.
1 (28 oz 794 g) can Las Palmas Red Chile Sauce, 3 beef bouillon cubes, ¼ cup plus 2 tbsps (~46 g) Gebhardt chile powder, 1 tbsp (6 g) ground cumin, 1 tbsp (3 g) dried oregano leaves, 2 tsps (5 g) onion powder, 1 tsp (3 g) garlic powder, 1 tsp (2 g) finely ground pepper, 5 lbs (2.27 kg) boneless beef chuck roast