I have been told that the SM2 uses a MK8 nozzle but I dont really know what this means. From a quick google search I see that MK8 nozzles use an M6 thread.
If this is the case would this nozzle fit? https://reprapworld.co.uk/products/extruder/brands/e3d/nozzles/1_75mm/e3d_v6_nozzle_x_0_40_mm_1_75_mm/
It is a M6 threaded nozzle. Would this seal properly and work with the existing heat block?