I believe Mike has spoken about the nocebo effect, but I don't recall specifically what he has said. As I understand it though, nocebo effects are a vastly different thing from the purported Powerful Placebo effect.
The difference may be the powerful physiological effect of nocebo in some cases. Robert Bartholomew has mentioned the case of a young man who decided to kill himself by using pills he had because he participated in a study. After having swallowed the pills, he regretted his decision and was taken to the hospital where they measured his symptoms, one of which was very high blood pressure. The people conducting the study were contacted about the effects of the pills, and they informed the hospital that this particular patient was in the placebo group. After he was told, his blood pressure normalized in 15 minutes.
In Project Brazen's podcast series about the 'Havana syndrome', mass psychogenic illness (MPI) is dismissed as the cause because one of the victims, Karen Coats, has retinal bleeding, which isn't usually a symptom of MPI. However, it can be a symptom of hypertension.