Both Sony NEX-5T and Nikon S9300 have 16.0 MP resolution sensors but Sony NEX-5T's sensor is APS-C (23.4 x 15.6 mm ) and Nikon S9300's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Sony NEX-5T's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Nikon S9300.
Below you can see the NEX-5T and S9300 sensor size comparison.
As seen above, Sony NEX-5T has a 13.0x Larger sensor area than Nikon S9300. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.