Nikon D5600 has a 24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Expeed 4 processor. On the other hand, Samsung NX1 has a 28.0MP APS-C (23.5 x 15.7 mm ) sized BSI-CMOS sensor and features DRIMe 5 processor.
Another similarity between these two cameras is that both Samsung NX1 and Nikon D5600 sensors lack anti-alias (Low-Pass) filters. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the D5600 and NX1 sensor size comparison.
Nikon D5600 and Samsung NX1 have almost the same sensor size so none of them has any significant advantage over other in this area.