Yes it's US but it's hard to find good products...The best thing you could do is contact some nurse niche brand/product/retail store/chain from the country with whom you have most followers from. (which let me guess is US?)
and come up with some kind of deal by showing them exactly how it can increase their profits best for their ROI.
Where can I check for CNA trainings? I think affiliate is the best choice. BTW it's good idea.What about CNA training? Back in the day these use to make good money on Adsense for me.