I too am not Tom, but like Tom, I too have used muriatic acid to strip chrome and reveal the underlying nickle.
I had some tire lock rings (not Model A) plated and was using them with stainless wheels. I couldn't decide whether nickle or chrome would be a better match. The plater suggested that he plate them with chrome, and if I didn't like it I could easily strip the chrome using muriatic acid to reveal the nickle plating. He also mentioned that the muriatic acid would not affect the nickle....except for darkening it if I left the ring in the acid too long.
As it turned out the chrome looked terrible against the stainless so I stripped the rings as suggested with muriatic acid. The first ring I stripped I didn't leave it in the acid long enough to dissolve the chrome. So I dipped it again, and again. After leaving it in the acid for a few minutes the nickle turned dark...just as the plater said would happen. I was, however, able to restore the nickle luster with polish.
Once I had the chrome removed I dipped the rings in a baking soda and water rinse to neutralize the acid.
For me the issue isn't whether or not muriatic acid will in any way damage the underlying nickle; it will not. It's what to do with the waste muriatic acid laced with chrome.... I put it in plastic bottles and delivered to the plating shop as I wanted no part in disposing of what I suspect was a hazardous material. The plating shop has both a hazardous materials license and means to dispose of hazardous materials.
Also, it's worth noting that while the muriatic acid will not affect the underlying nickle plating, it may well affect the underlying metal...such as pot metal. So far, I have used muriatic acid to stip chrome only from steel and brass parts...without encountering any problems.