He used to be the Admiral/General in Command of the Corporate Sector's security fleets and military forces, so he's got credentials.

That said, it was mainly an administrative job rather than mainly military. Cho has some experience, but he's not been in a position where victory was ever actually in question; he's always had all the numbers and resources he could call on to get a job done.

Now, where Cho has experience, I've never actually fleeted, though it's always interested me. Part of the reason for putting Cho into a single ship instead of, say, somehow getting him a fleet (on top of being hard to justify IC) was so that I could also get some practice in writing one ship rather than controlling a number of them at once.