Cook beans and chopped onions in 5-6 cups water until the beans are tender (approx. 4 hours). When water has cooked out of beans, add spices and mash with a potato masher or mixer. Add butter and 1 cup of the cheese, mix together. Sprinkle remaining cheese on top. Serve with nacho chips. You may add a few drops of hot sauce to taste and taco seasoning may be used instead of spices.