Nikon 1 S2 has a
14.2MP 1' (13.1 x 8.8 mm ) sized CMOS sensor and features Expeed 4A processor. On the other hand, Samsung NX mini has a
20.5MP 1' (13.2 x 8.8 mm ) sized BSI-CMOS sensor .
Samsung NX mini's sensor provides 6.3MP more than Nikon 1 S2's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the 1 S2 and NX mini sensor size comparison.
Nikon 1 S2 and Samsung NX mini have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.