It won't help you quite yet, but Google and Amazon resolved their issues around this in April[0] and their press release says you'll be able to watch Prime Vide

It won't help you quite yet, but Google and Amazon resolved their issues around this in April[0] and their press release says you'll be able to watch Prime Video on your Chromecast later in the year. [0] - https://press.aboutamazon.com/news-releases/news-release-details/amazon-and-google-announce-official-youtube-apps-launch-fire-tv https://press.aboutamazon.com/news-releases/news-release-det...