Why is Z-Nylon not available for the M200 and M300?
As M200 Plus and M300 Plus have upgraded extruder and hotend geometry combined with better cooling system, they are capable of printing more demanding materials. Remember that these printers use new Hotend v3 that has better heat distribution. As always, you can try to print Z-NYLON with "external materials" options on M200, but we are not be able to guarantee the same results as with M200 Plus and M300 Plus.
You say, "As always, you can try to print Z-NYLON with" external materials "options on M200, but we are not able to guarantee the same results as M200 Plus and M300 Plus."
Ok, but can you still tell us the basic parameters to try: T ° filament, T ° aluminum plate, print speed and shrink parameters ?
Whether z-nylon prints nice or not on v2 hotend will depend on the specific formulation of z-nylon (nylons have large variations in formulation and mech properties); Julia did some testing with nylon filaments and found some print nicely on v2 hotend while others did not. I'm going to give z-nylon a try on v2 when it's available even though it might not print as well as on v3.
Also, and I'm not sure if it's significant or not, but I noticed the Z-Nylon profile has a unique raft layering not available in available external material profiles, possibly other changes; maybe nice to have if it helps across nylons.