The second display of Google Home appears: you get more results than YouTube videos on your Chromecast.
Video Chromecast news
Returning to I/O 2017, they promised us visual feedback from Google Home on a Chromecast and waited for months to show up. A few weeks ago, the first one started working: you could ask Google Home to show you the weather on your TV and instead of responding with the forecast, it will invoke your connected Chromecast and show the weather conditions on the TV. The same is happening now for YouTube video results.
Ryne tested it by asking Google Home: “show me the Aqua Teen Hunger Force videos on YouTube on my Chromecast” and got more video and thumbnail results as a response to his TV. Previously, Home automatically starts playing the first video and does not give you the ability to view more results. It does not work consistently for everyone, so you could test it a few times to see if it works for you based on your location, language, Chromecast generation, Home firmware version, etc. Etc.
There are many variables and know for sure when / where it will work and when / where it will not be impossible until Google will publish an official support page for views (and even then …).
Technically speaking, you should be able to follow up by saying “Ok Google, play the third”, for example, and you might be able to truncate the command simply “show me xyz videos on my TV / on my Chromecast,” but more tests are needed and I can not do it since I have Android TV and those are the abandoned children of Home integration … half of the commands do not work on them.