A bit of an overstatement, to say the least. Here are just a few verses from both versions, chosen at random - I didn't deliberately look for verses in which the versions were most similar. (AV=KJV):
Genesis 1.6:
(AV) And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.
(NKJV) Then God said, "Let there be a firmament in the midst of the waters, and let it divide the waters from the waters."
1 Kings 10.5:
(AV) And the meat of his table, and the sitting of his servants, and the attendance of his ministers, and their apparel, and his cupbearers, and his ascent by which he went up unto the house of the LORD; there was no more spirit in her.
(NKJV) the food on his table, the seating of his servants, the service of his waiters and their apparel, his cupbearers, and his entryway by which he went up to the house of the LORD, there was no more spirit in her.
Psalm 119.116:
(AV) Uphold me according unto thy word, that I may live: and let me not be ashamed of my hope.
(NKJV) Uphold me according to Your word, that I may live; And do not let me be ashamed of my hope.
Mark 14.35:
(AV) And he went forward a little, and fell on the ground, and prayed that, if it were possible, the hour might pass from him.
(NKJV) He went a little farther, and fell on the ground, and prayed that if it were possible, the hour might pass from Him.
2 Timothy 4.2:
(AV) Preach the word; be instant in season, out of season; reprove, rebuke, exhort with all longsuffering and doctrine.
2 (NKJV) Preach the word! Be ready in season and out of season. Convince, rebuke, exhort, with all longsuffering and teaching.
It seems to me that your assertion about the NKJV being "nothing like" the KJV is mistaken.