If you load a stream in a mobile browser, the chat appears but it doesn’t appear to let you type in it. It seems to be a read-only type of deal.
I’ve asked other people to test this and they confirm the same thing… You can also get this to happen if you open a Twitch stream in Chrome’s mobile view from the dev tools. Be sure to refresh to trigger the https://m.twitch.tv) URL to properly be in the mobile view though.
Is this intentional?