If this holds up it will be the first-ever no-hitter against the Nationals since the move; the last no-no against the combined Expos/Nationals franchise was on 18th July 1999, by David Cone of the Yankees in an interleague match (score 6-nil). The last no-hitter against the Expos by a National Leaguer was by Tommy Greene of the Phillies on 23rd May 1991 (score 2-nil).
Marlins pitchers have thrown four no-hitters...most recently by today's starter against the Diamondbacks on 6th September 2006 (score 2-nil).