Yes, you're right that the JR pass doesn't cover Nozomi trains. You can take other Shinkansen, like the HIKARI or KODAMA, from Nagoya to Hiroshima instead. You'll need to change trains in Shin-Osaka or Shin-Kobe on the way. It's little slower, but easy enough to do.
On HyperDia, if after entering your departure and arrival stations you click on "more options", you can unclick "Nozomi/Mizuho trains" and "private railway" to leave them out of the search results. This way you'll only see routes you can take using your JR Pass.
Comments
Yes, you're right that the JR pass doesn't cover Nozomi trains. You can take other Shinkansen, like the HIKARI or KODAMA, from Nagoya to Hiroshima instead. You'll need to change trains in Shin-Osaka or Shin-Kobe on the way. It's little slower, but easy enough to do.
On HyperDia, if after entering your departure and arrival stations you click on "more options", you can unclick "Nozomi/Mizuho trains" and "private railway" to leave them out of the search results. This way you'll only see routes you can take using your JR Pass.
I hope this helps!
Japan Experience