Put onion slices on a sheet of aluminum foil. Top with the butter and seasoning. Seal and place over indirect heat on the grill for about 20 minutes or until the onion gets soft. Remove.
Warm the chili.
Mix coleslaw vegetables and dressing. Refrigerate until ready to serve.
Grill the dogs and toast the buns as desired.
Serve dogs topped with onion, chili, cheese and slaw.