O King of nations - i. e., pagan nations. Yahweh is not the national God of the Jews only, but He reigns over all mankind Psalms 22:28.
It - i. e., everything.
In all their kingdoms - More correctly, “in all their royalty or kingship.”
Related Commentaries of Jeremiah 10:7
Jeremiah 10:7
7 Who would not fear thee, O King of nations? for to thee doth it appertain: forasmuch as among all the wise men of the nations, and in all their kingdoms, there is none like unto thee.