Thistle hope to have Nitriansky, 26, in Saturday's squad to face Hibernian.
He has turned out for five clubs in his homeland, including Slavia Prague, and also played in Italy with Avellino.
Defenders Niall Keown and Jordan Turnbull, midfielder Blair Spittal and goalkeeper Jamie Sneddon have also joined the Jags for this season.
Find all the latest football transfers on our dedicated page.
Czech defender Milan Nitriansky has joined Partick Thistle on a deal until the end of the season, subject to international clearance.