You certainly can! All you have to do is to add another YouTube account from mimoLive’s preferences, and you will be able to select which account you want to stream to from a dropdown in the Live Streaming output destination. You can even stream simultaneously to both YouTube channels if you create a different live streaming output destination for each one!
(By the way, even if you don’t add the secondary YouTube account to mimoLive, you can live stream to any YouTube channel using RTMP.)