The inside-the-law approach that works to some limited extent is public community rejection. Things like large groups showing up and standing with their back to the Nazis.
The method that has historically stopped Nazis like this involves getting some level of police cooperation and beating them up
Do what punks did to keep them out of the punk scene. Make them feel afraid to show up. You do this by beating the shit out of every single one of them every time they show up or open their mouths.