To clarify, SHBG is not binding to nandrolone decanoate (Deca-Durabolin)—it's binding to the nandrolone after it's been freed from the ester. The
Wiki page on SHBG says that testosterone has 19 times the binding affinity of nandrolone. To me this suggests that you'd have to have an awful lot of nandrolone to make much difference via competitive inhibition. Mesterolone (Proviron) has 440 times the binding affinity of nandrolone, so, setting aside legality and availability, why not prefer it for freeing up testosterone? It would take a lot less to do the job, potentially offsetting its—possibly undesirable—greater androgenic effects.
Your new paraphrasing of Dr. Lichten seems more equivocal, possibly only referring to competitive inhibition. Can you provide any direct quotes from him saying that nandrolone is influencing the actual binding affinity of nandrolone? People, myself included, say incorrect things all the time without intentionally lying. On this particular point I think madman has the stronger case, but his counterproductive ad hominem attacks distract from the science-based arguments.