Nikon B500 has a
16.0MP 1/2.3 (6.17 x 4.55 mm ) sized BSI-CMOS sensor . On the other hand, YI M1 has a
20.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor .
Below you can see the B500 and M1 sensor size comparison.
As seen above, YI M1 has a 8.0x Larger sensor area than Nikon B500. 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.