You're not just able to go in and change your mind every week, but once in every 30-day period, Mixer lets you change your username. Even this is fantastic since some other services, looking at you Twitch, don't allow changes at all without creating a new account.
This may well become redundant when future changes involving Xbox Live come into effect with gamertags and what not, but at least for now, here's how you go about changing your handle.
- Click on your avatar in the top right-hand corner of the screen.
Next, click on account.
Second in along the top you now want to access account & security.
- Under change username enter what you want your new channel to be called.
Your new channel and username will be created now, with the existing URL for your old one being redirected for 30-days before being removed. So if you wished you'd been more original, at least for now go on ahead and get the name you really want!