I've written Mandalorians on and off for years. My first family of 'em way back years ago on another site where the Mandalorian population was pretty small, the patriarch was an alternate clone template; pretty intimidating man, I used Dolph Lundgren for his playby.
There's always been a not-small to sizeable contingent of Mandalorian characters on Chaos since the very beginning, far as I can tell - been here since late January 2014 (my 10 year anniversary approaches!), got involved with Mandalorians on an individual clan level (Clan Rekali) and with one to two of the major/active Mando factions that's existed in the past, with my own small, unique clan (Clan Quez), and with someone else's small clan (Clan Ahn-Dross).
But haven't been much involved with Mando RP since a good while prior to The Mandalorian, so I can't speak to whether that has caused a significant influx at all, or if it's simply brought things back up to prior levels.