Nikon Z7 II has a
46.0MP Full frame (35.9 x 23.9 mm ) sized BSI-CMOS sensor and features Dual Expeed 6 processor. On the other hand, Canon 1D C has a
18.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Dual Digic 5+ processor.
Nikon Z7 II's sensor provides 28MP more than Canon 1D C'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.
Another difference between these two cameras is that Nikon Z7 II'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 Z7 Mark II and 1D C sensor size comparison.
Nikon Z7 II and Canon 1D C have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.