Nikon D7500 has a
21.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features Expeed 5 processor. On the other hand, Samsung NX300M has a
20.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features DRIMe IV processor.
Another difference between these two cameras is that Nikon D7500'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 moiré occurring in certain scenes.
Below you can see the D7500 and NX300M sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D7500 and Samsung NX300M Cameras
Nikon D7500 and Samsung NX300M have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Nikon D7500
or the
Samsung NX300M ,
including hyperfocal distance.