Both Sony WX1 and Nikon P7100 have 10.0 MP resolution sensors but Sony WX1's sensor is 1/2.4-inch (6.104 x 4.578 mm ) and Nikon P7100's sensor is 1/1.7-inch (7.44 x 5.58 mm ).
Since Nikon P7100'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 Sony WX1.
Below you can see the WX1 and P7100 sensor size comparison.
As seen above, Nikon P7100 has a 1.5x Larger sensor area than Sony WX1. 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.