Both Olympus VR-320 and Nikon 1 J3 have 14.0 MP resolution sensors but Olympus VR-320's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Nikon 1 J3's sensor is 1-inch (13.2 x 8.8 mm ).
Since Nikon 1 J3'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 Olympus VR-320.
Below you can see the VR-320 and 1 J3 sensor size comparison.
As seen above, Nikon 1 J3 has a 4.1x Larger sensor area than Olympus VR-320. 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.