Leica TL has a 16.0MP APS-C (23.6 x 15.7 mm ) sized CMOS sensor . On the other hand, 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.
Nikon Z7 II's sensor provides 30MP more than Leica TL'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.
One other difference between these two cameras that is worth mentioning is that Nikon Z7 II's sensor doesn't have an 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 TL and Z7 Mark II sensor size comparison.
![Leica TL vs Nikon Z7 II Sensor Size Comparison]()
Sensor Size and Resolution Comparison image of Leica TL and Nikon Z7 II Cameras
As seen above, Nikon Z7 II has a 2.3x Larger sensor area than Leica TL. 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.