If I were to dice a cuber that would not be eaten for another 8 hours, how would I store it?

I'm making crock pot tacos for dinner and I want to dig right in when I get home after a long day. I want to dice my cuber in the morning to use as a garnish for the tacos instead of lettuce, so what would be the best method of storing them for optimal taste and freshness when I go to eat it for dinner later that night?