Do you mean they receive a new stream key when they login, or a new chat oauth token (I don’t stream or use xsplit, so I’m just not completely sure what you mean)? If you go here: http://www.twitch.tv/settings/connections and “TMI Token Gen” isn’t listed at the bottom under “Other Connections”, then you likely mean a different kind of token; in which case I’d go with what Barry is saying. You can make a bot that logs into chat separately with each streamer’s username / token pair, and performs the /mod or /unmod command.
Or if the xsplit wizard is using that application too, this is the link for creating your own application: http://www.twitch.tv/kraken/oauth2/clients/new though it might take a little bit of work to set one up. The application would only need to be created and added once, and I believe you can generate a token that doesn’t expire so you’d only need to do that once too, and then save the info in a config file for the bot.