Originally Posted by Ren Ching
I wonder if perhaps you have it set up wrong. Usually thise things borrow an existing bolt hole. In any event, if you can't use an existing hole, install a riv nut in the side of the chassis. A fine thread sheet metal screw would work too but the riv nut would be a little better. The only stress on those fasteners will be from vibration or if you whack the step on a rock or tree stump.
Pete, I don't believe these sidesteps were specific for the NAS model and require drilling.