We need to look at the underlying Old Testament text alluded to in both passages:
Psa 2:1 Why do the nations rage and the peoples plot in vain?
Psa 2:2 The kings of the earth set themselves, and the rulers take counsel together, against the LORD and against his Anointed, saying,
Psa 2:3 “Let us burst their bonds apart and cast away their cords from us.”
Psa 2:4 He who sits in the heavens laughs; the Lord holds them in derision.
Psa 2:5 Then he will speak to them in his wrath, and terrify them in his fury, saying,
Psa 2:6 “As for me, I have set my King on Zion, my holy hill.”
Psa 2:7 I will tell of the decree: The LORD said to me, “You are my Son; today I have begotten you.
Psa 2:8 Ask of me, and I will make the nations your heritage, and the ends of the earth your possession.
Psa 2:9 You shall break them with a rod of iron and dash them in pieces like a potter's vessel.”
Psa 2:10 Now therefore, O kings, be wise; be warned, O rulers of the earth.
Psa 2:11 Serve the LORD with fear, and rejoice with trembling.
Psa 2:12 Kiss the Son, lest he be angry, and you perish in the way, for his wrath is quickly kindled. Blessed are all who take refuge in him.
We have reference to the nations, and to kings. The kings are warned to serve the Lord, or they will perish.
Revelation 2 refers to Psalm 2:9
Rev 2:26 The one who conquers and who keeps my works until the end, to him I will give authority over the nations,
Rev 2:27 and he will rule them with a rod of iron, as when earthen pots are broken in pieces, even as I myself have received authority from my Father.
But there is some significant new information here. The authority spoken of in Rev. 2 is "authority over the nations". But it is delegated authority from Christ to the overcoming believer.
So to say that the authority spoken of is limited to destroying the wicked at the coming of Jesus makes no sense here, because the believer is not the one smiting the wicked at Jesus' coming.
But according to Rev. 20 some are reigning with Christ. And here it says they have authority over the NATIONS.
Now in Revelation 19 we see Psalm 2:9 referenced again:
Rev 19:15 From his mouth comes a sharp sword with which to strike down the nations, and he will rule them with a rod of iron. He will tread the winepress of the fury of the wrath of God the Almighty.
Rev 19:16 On his robe and on his thigh he has a name written, King of kings and Lord of lords.
Rev 19:17 Then I saw an angel standing in the sun, and with a loud voice he called to all the birds that fly directly overhead, “Come, gather for the great supper of God,
Rev 19:18 to eat the flesh of kings, the flesh of captains, the flesh of mighty men, the flesh of horses and their riders, and the flesh of all, both free and slave, both small and great.”
Rev 19:19 And I saw the beast and the kings of the earth with their armies gathered to make war against him who was sitting on the horse and against his army.
Rev 19:20 And the beast was captured, and with it the false prophet who in its presence had done the signs by which he deceived those who had received the mark of the beast and those who worshiped its image. These two were thrown alive into the lake of fire that burns with sulfur.
Rev 19:21 And the rest were slain by the sword that came from the mouth of him who was sitting on the horse, and all the birds were gorged with their flesh.
Jesus comes as King of Kings and Lord of Lords. And He destroys the kings and their armies gathered to resist Him. Just as in Psalm 2 where the kings are warned to submit or they will perish.
The birds are gathered to this place as well to eat of the flesh of the armies of the kings, including the horses.
So we see the kings who resist Christ shattered, and slain in a battle in a particular spot where they are gathered.
Previously Christ ruled over the nations through delegated authority, through servants (Rom. 13), but now directly. The kings did not submit and perished.
The kings and their armies are gone. But the nations are not. Satan is bound so that he might not deceive the nations:
Rev 20:2 And he seized the dragon, that ancient serpent, who is the devil and Satan, and bound him for a thousand years,
Rev 20:3 and threw him into the pit, and shut it and sealed it over him, so that he might not deceive the nations any longer, until the thousand years were ended. After that he must be released for a little while.
Then we see those given authority to reign with Christ:
Rev 20:4 Then I saw thrones, and seated on them were those to whom the authority to judge was committed. Also I saw the souls of those who had been beheaded for the testimony of Jesus and for the word of God, and those who had not worshiped the beast or its image and had not received its mark on their foreheads or their hands. They came to life and reigned with Christ for a thousand years.
What are Christ and these who are given authority reigning over? The nations which is stated in Rev. 2
Rev 2:26 The one who conquers and who keeps my works until the end, to him I will give authority over the nations,
Rev 2:27 and he will rule them with a rod of iron, as when earthen pots are broken in pieces, even as I myself have received authority from my Father.
Jesus slays the kings and their armies, and reigns over their nations, along with those He gave authority.