Can I be sued if I accused a co-worker from stealing tips at a restaurant?

Anyone can be sued, but as a lawyer I am not interested in suing anyone for such a thing (certainly not on a no recovery no fee basis also called a contingency fee basis), and I doubt if the person can pay a lawyer to sue you under any other fee arrangement. While it's not legal advice but merely practical thoughts here, I would not worry about being sued, but about the conflict itself and how to resolve it without getting fired or having to work at someone who is upset with you.

Yes, you may be sued for this in GA. But they would have to show real $$ damages to win no speculation as to the damages.

Sure, but truth is a defense and the amount of damages to be recovered from you would probably be so small that I don't think any attorney would take the case.