Tamiya is a synthetic lacquer..any lacquer paint will work..
best option is Tamiya TS-13 clear. its good stuff, put a couple mist coats down for base, then lay down a few wet coats.it goes on very thin, like all tamiya paint, so you will need the heavier wet coats at the ends...
its best to clear over tamiya within 30 minutes or wait 30 days..
I have waited 24 hours to clear, and didnt have an issue, but have heard that was pushing it..
I have used Testors model master lacquer clear over Tamiya with mixed results. I dont think Tamiya gloss black likes anything other than Tamiya clear. but I put it over a tamiya chrome yellow base and tamiya pearl clear mid coat with great results.
duplicolor import touch up paint clear, is another option. its also lacquer, but i havent tried it over tamiya...