We tested to print quite successfully nylon PA6 with micro-carbon filament. For printing on the Replicator + (pa6_c4_rep) and the Replicator Z18 (pa6_c4) we used amongst other things the MakerBot Experimental Extruder with a 0.4mm hardened Nozzle. You can find more information at: https://www.3d-edu.ch/nylon-pa6-mit-mikro-karbonfasern-mit-makerbot-drucken/
These print modes here are to serve you as a starting point. We would be happy about further improvements.