Nikon Z6 has a 24.0MP Full frame (35.9 x 23.9 mm ) sized BSI-CMOS sensor and features Expeed 6 processor. You can shoot at maximum resolution of 6048 x 4024 pixels with aspect ratios of 1:1, 5:4, 3:2 and 16:9. Z6 has a native ISO range of 100 - 51200 which can be boosted to 50 - 204800 and it can save files in RAW format which gives you a wider room for post processing.
Nikon Z6 is not the highest resolution Full frame camera. Blackmagic PYXIS 12K with its 98.8MP sensor is leading in this class. Check the comparison of Nikon Z6 vs Blackmagic PYXIS 12K or take a look at Highest resolution Mirrorless cameras list.
Nikon Z6 DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. Nikon Z6 sensor has been tested by DxO Mark and got an overall score of 95 for its image quality. You can find the details of their analysis of Nikon Z6 here.
Let's look at how the size of the Nikon Z6's Full frame sensor compares with other standard sensor sizes.
Comparison image of Nikon Z6 Sensor Size with other standard sensors
Sensor size is what determines the circle of confusion, and therefore how much
depth of field Nikon Z6 gives you at any given aperture.
You can
calculate
the exact depth of field for the Nikon Z6
at any focal length, aperture and subject distance, including the hyperfocal distance
for landscapes and the very shallow focus zone you get with long telephoto lenses.