I am not a scholar but the difference between NIV and KJV is partly due to the fact that NIV relies on Septuaginta (which is translated into Greek), and not the Masoretic Text. Which is, Hebrew.
So what I want to say is that according to Pastor Benny Hinn, who has read Hebrew from since he was young, gives an opinion on the translation made in KJV and practically all other translations based on the MT, which reads:
So shall they fear the name of the LORD from the west, and his glory from the rising of the sun. When the enemy shall come in like a flood, the Spirit of the LORD shall lift up a standard against him.
But according to Hinn, in the original Hebrew, there is not a comma after the "flood". (Hinn 2004) So it could be most likely be like this, by just changing the place of the comma:
So shall they fear the name of the LORD from the west, and his glory from the rising of the sun. When the enemy shall come in, like a flood the Spirit of the LORD shall lift up a standard against him."
Source:
Hinn, B. "Good Morning, Holy Spirit", 2004, Thomas Nelson Publishers