You definitely don't have to Odin to upgrade to a newer nightly.
Unfortunately FE, I'm going to have to as I can't get into recovery. Things have been crazy around my house as my wife and I are gearing up for 2 big events with the dog rescue foundation we work with.. I'm hopeful that I can get the time to odin to stock and go to a newer nightly some time this coming weekend.
But I have successfully flashed from one nightly to a newer one, just by flashing over the top (clearing cache and system of course.)