Hi Danny, Nozomi and Mizuho Shinkansen is not included in the Japan Rail Pass.

JR did however introduce the option to purchase a seat upgrade to Nozomi and Mizuho on October 1st. The price is usually not worth it though, depends on your journey. The time difference from Tokyo to Kyoto between Nozomi Shinkasen and Hikari Shinkansen which is included in your Japan Rail Pass is only 13 minutes on a 2.5 hour loung journey.
Below is a couple of priceexamples if you wish to upgrade. Keep in mind that the prices are per single way.

Tokyo to Nagoya – 4,180 JPY

Tokyo to Kyoto – 4,960 JPY

Tokyo to Shin-Osaka – 4,960 JPY

Tokyo to Hiroshima – 6,500 JPY

Shin-Osaka to Hakata – 4,960 JPY

Kyoto to Himeji – 2,530 JPY

Tokuyama to Tokyo – 7,040 JPY

Shin-Kobe to Hiroshima – 4,170 JPY

Kyoto to Hiroshima – 4,170 JPY

Nagoya to Okayama – 4,170 JPY

Fukuyama to Kyoto – 4,170 JPY

Hiroshima to Kumamoto – 5,930 JPY

Nagoya to Kokura – 5,930 JPY

Shin-Osaka to Tokuyama – 4,620 JPY

Shin-Osaka to Sendai – 8,830 JPY

Sendai to Hakata – 3,870 JPY

You can find more information, purchase locations and all Nozomi / Mizuho prices here: https://getjrpass.com/nozomi-mizuho/

Hope it was of help and have a wonderful stay in Japan!
With kind regards, Jonathan H.
Getjrpass Staff