Pour the enchilada sauce and apple butter in a crock-pot. Place the beef roast in it, followed by sliced onions, garlic, salt, and red pepper. Cover and turn the crock-pot on high for 4-5 hours, until the beef is falling apart.
Using two forks, shred the beef roast into the sauce, and leave on warm until ready to serve.
For the Beef Nachos:
Preheat the oven to 350 degree F. Arrange the tortilla chips on a large rimmed baking sheet. Sprinkle half the cheese over the top and bake for 3-5 minutes to melt the cheese.
Scoop the chili con carne over the chips, and sprinkle the remaining cheese over the hot beef. Top with any additional toppings and serve immediately.