Since the pots are going to be stacked on the chain, you need something to keep the chain from sliding through. It needs to be something large enough so that can't slip through the bottom no matter how it is positioned. This is just in case it somehow moves. An easy way to do this is to get a bolt, a nut that fits on the bolt, and a washer that cannot slide off the nut and the large end of the bolt.
How to arrange this
1. Slide the bolt through the bottom link in the chain
2. Slide the washer on
3. Screw on the bolt
I didn't use use one of the hooks I took off of the fish stringer because I just didn't like the way it looked.
You can use any other method that works, I just used items that were on hand. You can post your own method in the comments section for other people to try. Or, if you are other people, you could try looking in the comments section for another method if you need one.