So we can’t project direct from the ZWIFT app to a TV using Chromecast, but you can use the Streamer for Chromecast App to mirror your Android or iOS device on to your TV.
Open the Streamer for Chromecast App then:
1) Run the Streamer for Chromecast app on your iOS device (iPhone or iPad).
(2) The app will automatically search for the Chromecast device. Select your Chromecast device.
Cheers