The nations will NOT be in flesh and blood bodies during Christ's future Millennium reign. You still don't get it. God's consuming fire will end this present flesh world:
2 Peter 3:10-13
10 But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.
11 Seeing then that all these things shall be dissolved, what manner of persons ought ye to be in all holy conversation and godliness,
12 Looking for and hasting unto the coming of the day of God, wherein the heavens being on fire shall be dissolved, and the elements shall melt with fervent heat?
13 Nevertheless we, according to his promise, look for new heavens and a new earth, wherein dwelleth righteousness.
KJV
ALL... peoples after that event on the day of Jesus' return, will be in incorruptible bodies, including the unsaved nations. In Zechariah 14 we are told that after Jesus' return, all nations will be required to come up to Jerusalem to worship the King from year to year, and keep the feast of tabernacles. And it includes those of the nations left over from the armies that came against Jerusalem on the last day of this world. That is the wicked, also who are unsaved during the 1,000 years. The rest of the "nations" of Rev.20 are also the unsaved. Only those inside the gates of Rev.22:14-15 are the saints.