Nikon 1 J4 has a
18.0MP 1' (13.2 x 8.8 mm ) sized CMOS sensor and features Expeed 4 processor. On the other hand, Olympus 8010 has a
13.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features TruePic III processor.
Nikon 1 J4's sensor provides 5MP more than Olympus 8010'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 J4 and 8010 sensor size comparison.
As seen above, Nikon 1 J4 has a 4.2x Larger sensor area than Olympus 8010. 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.