Brown the ground beef and onions in a large skillet. Drain. Transfer into a large crockpot. Add all of the rest of the ingredients except the corn chips.
Cover and cook on low 6-8 hours. Place a handful of the corn chips into a soup bowl and pour a big scoopful of soup over the chips. Serve with chopped green chilies, shredded cheddar cheese and sour cream if desired.