Folding chairs? If there is some open space at the top of the chair it’s easy. Get some 1” square tube, make a rectangular piece the depth of the rack and to the top of your tail lights with a cross bar about 6 inches down, and weld some hooks on the outside. Weld the down tubes to the existing corner down tubes of the rack. You could carry 3-4 chairs a side on the hooks with some bungee cords or ratchet straps. If you want bonus points for doing it the best way possible, you could add a shelf with a sill at the bottom to hold the legs. Shouldn’t add that much weight or stress, and having the chairs with the sides into the wind instead of the back shouldn’t cause too much drag. You could even add a top shelf across the new side brackets, but I’d be worried about over doing it. The single mounting point of those racks makes me nervous, even though I know the receiver is made to carry more weight than I could ever get on the rack.
By the way, is that bent or just the picture? How did you manage to bend it if so?