This was found a long time ago by my neighbour who has now passed it on to me. It has NAX IOIA on the coin with what I believe to be a kings or gods face on one side and some grapes and vines on the other.
It looks like a modern tourist souvenir. The inscription actually reads NAX IOIA.
These medallions are usually something like 6 - 8 cm across, and are very loosely based on the design of coins like this silver Drachm from Naxos:
The original shows the head of the god Dionysus on the obverse, and a bunch of grapes on stalk with two leaves on the reverse. The inscription on the reverse was originally NAC ION (which is perhaps rather less-recognisable to tourists), and the difference in the quality of the images between the original coin and the modern souvenir is very noticeable.
Your medallion is probably cast, rather than hammered, although I can't make out enough of the edge detail from your photograph to be certain. I've seen medallions like that sold online from time-to-time. They usually sell for a few pounds Sterling.
EDIT: This gilded example (which was actually 57mm in diameter) sold for 25,000 Hungarian Florint (about £7.00 GB at current exchange rates) in 2013.