Here are the facts that are the basis for my statement.
I challenge any KJV-only advocate to present a list of claimed greater textual differences between the KJV and the NKJV than those that I will list between the 1560 Geneva Bible and the KJV that KJV-only advocates have asserted are "basically the same Bibles" or are "practically identical."
Matthew 1:11 "Jacim. And Jacim begat" [these words in 1560 Geneva Bible are not in the 1611 KJV] [see also 1611 edition's marginal note]
Matthew 26:26 "and when he had given thanks" [1560 Geneva]
"and blessed it" [1611 KJV] [see 1611 marginal note]
Mark 15:3 "but he answered not" [these words in KJV are not in 1560 Geneva Bible]
Luke 10:22 "Then he turned to his disciples" [these words in 1560 Geneva Bible are not in 1611 KJV's text] [see 1611 marginal note]
Luke 17:36 [this verse in the KJV is not in the 1560 Geneva Bible]
The 1560 Geneva Bible has a verse 36 but it is what is verse 37 in the KJV. [see 1611 marginal note]
John 8:6 "as though he heard them not" [these words in KJV are not in 1560 Geneva Bible]
John 8:59 "going through the midst of them, and so passed by" [these words in KJV are not in 1560 Geneva Bible]
John 14:1 "And he said to his disciples" [1560 Geneva] [these words not in KJV]
Romans 8:11 "because that his Spirit" [1560 Geneva]
"by his Spirit" [1611 KJV]
see 1611 marginal note, and see Hills, KJV Defended, p. 222 where he
presented this as a textual difference between the TR editions by Beza and those by Erasmus and Stephanus
1 Corinthians 15:31 "our rejoicing" [1560 Geneva]
"your rejoicing" [1611 KJV] [see 1611 marginal note]
1 John 2:23b [but] he that acknowledgeth the Son hath the Father also
[this second half of this verse in KJV is not in 1560 Geneva Bible]
Revelation 16:5
and Holy [1560 Geneva Bible]
and shall be [1611 KJV] [KJV followed conjecture introduced by Beza]
So if they will receive the geneva as OK, for sure should see the Nkjv in same light?