Fujifilm X-T20 has a 24.0MP APS-C (23.6 x 15.6 mm ) sized CMOS X-TRANS III sensor and features X-Processor Pro2 processor. On the other hand, Nikon 1 J5 has a 21.0MP 1-inch (13.2 x 8.8 mm ) sized BSI-CMOS sensor and features Expeed 5A processor.
Another similarity between these two cameras is that both Nikon 1 J5 and Fujifilm X-T20 sensors lack anti-alias (Low-Pass) filters. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the X-T20 and J5 sensor size comparison.
As seen above, Fujifilm X-T20 has a 3.2x Larger sensor area than Nikon 1 J5. 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.