This is another confirmation by Nephi of what was written before. The Nephites will have the records of the Jews and lost tribes of Israel, and the Jews and the lost tribes will have the records of the Nephites. "The things of all nations" will include these various Divine messages and teachings given to the various nations/people of the earth. The "children of men" in that day will have available to them the records that allow them to see how the knowledge of the Lord will cover the earth as the waters cover the sea. They will realize that these distant echoes of the Gospel which appear in other faiths, traditions and sacred texts were, at one time, an authentic communication from the Lord or His servants.
So much of what appears to contradict will be found to have a common root. The things that have been sealed and kept from public discourse will become part of the public dialogue. We will not have the same requirement for "secrets" to be kept. But "nothing which is secret" will remain so. It will all "be revealed."
When the truth is unsealed, so are the conspiracies, the foolishness and the ambitions that have worked to keep the truth from becoming known. None of the "work of darkness" which has been afoot will be kept from public view, but "it shall be manifest in the light." Whatever excuses men have had to suppress the truth, deny the Spirit, and employ the "arm of flesh" as their guide will be exposed for what they are. They will put on display. The wisdom of the wise will be seen for the foolishness it was. The strength of man's arm, the studied foolishness gained from social sciences, opinion polling, focus groups and other attempts to figure out where the ignorant are going and jump in front of the trend to feign leadership, will be seen for what it was. The endless praise and adoration given to these foolish and weak political, governmental, business, educational and "moral" leaders will be seen for what it was.
Oh the wisdom of God and the foolishness of men! When men are educated they think they are wise. (2 Nephi 9: 28.) All the studied ignorance of men will be recognized as foolishness, rather than as wisdom as it is now. (1 Cor. 3: 19.) Then the fools will at last shut their mouths and cease to thunder out their errors. (Isa. 52: 15.)
You can almost feel Nephi's relief as he contemplates this outcome. The final vindication of the truth. The final conquest of the foolishness of men. It is consoling to consider that this odd and corrupt world we find ourselves in will at some point finally end. The truth will be vindicated. The errors and evil we enshrine in our institutions and art will collapse. We will emerge from behind the scales of darkness covering our eyes and at last see things as they are in the light of heaven.