Dave, you might move the clown and anemone to the nano. Then the clown will find the anemone in the small space. Once it finds it, move them both back to the big tank. You could even add another small clown so they pair up prior to the move. This has worked for me in the past.
Or try the trick McBeck taught me. Put the clown in the nano with a small terra cotta flower pot. Wait until he begins to host in it. Then move the clown and pot back to your big tank, positioning the pot right below an anemone. That worked great too.
I still have the small pot in my sump in case someone wants to use it. You can get it next weekend if you want it.