Nikon 1 J5 has a 21.0MP 1" (13.2 x 8.8 mm ) sized BSI-CMOS sensor and features Expeed 5A processor. On the other hand, Canon G9 X II has a 20.0MP 1″ (13.2 x 8.8 mm ) sized BSI-CMOS sensor and features DIGIC 7 processor.
Another difference between these two cameras is that Nikon 1 J5's sensor lacks anti-alias (Low-Pass) filter. 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 J5 and G9 X II sensor size comparison.
Nikon 1 J5 and Canon G9 X II have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.