I have read and studied the KJV over 50 years. The last few years I have also been reading and studying the NKJV. I have usually carried a KJV/NKJV Parallel Bible to church with me the last few years so I can see them side-by-side.
KJV-only advocates have praised the 1560 Geneva Bible, and some of them will suggest that the 1560 Geneva Bible is basically the same Bible or is practically identical to the KJV.
I have compared many renderings in the 1560 Geneva Bible, the KJV, and the NKJV. In many places where the makers of the KJV improved on the renderings in the Geneva Bible, usually the NKJV basically follows or keeps the KJV’s renderings, sometimes merely updating the spelling or English.
One important example in the Old Testament of where the makers of the KJV improve on the Geneva Bible is in the fact that the KJV indicates for readers a distinction between which Hebrew name is used for God by having “LORD” or “GOD” for the Hebrew name which was also translated Jehovah eight times in the KJV while the Geneva Bible does not. This one case would involve over 5,000 places where the KJV could be considered to have improved on renderings in the Geneva Bible. The NKJV also has these over 5,000 improvements to the Geneva Bible’s Old Testament.
Since the NKJV is certainly an improvement over the Geneva Bible in a large number of places, what does that suggest about the positive praise for the Geneva Bible on the part of KJV-only advocates when compared to their extremely negative attacks on the NKJV?
Since the NKJV translators kept or followed many of the improvements made to the Geneva Bible by the KJV translators, could it suggest that the NKJV could be considered more practically identical to the KJV than the Geneva Bible is?
I have also found several pages of examples where the 1560 Geneva Bible could be considered clearer, better, or more accurate than the KJV, and the NKJV usually is in agreement with the Geneva Bible in those cases.
Considering that the NKJV keeps most of the best of both the 1560 Geneva Bible and the KJV, it would suggest that it is likely better overall than the KJV.