Nations?
Is this in reference to human beings? As the result of the bowls of God’s judgments:
a) The salt water sea was poisoned killing every living thing in it (Rev 16:3).
b) Fresh water springs and rivers were poisoned (Rev 16:4-6).
c) The sun became exceedingly hot (Rev 16:8) and likely scorched any agriculture.
d) A massive earthquake and hailstorm (Rev 16:17-21) likely killed many.
As a consequence of God's bowl judgments resulting in life without water, food, and shelter, and the demise of the military at
Armageddon marking the end of Daniel's seventy weeks (Dan 9:24-27), the death of all human
beings would be the "end of sin" (Dan 9:24).
The only personal beings left on earth would be fallen angels who followed Satan. Observe carefully that it is "fire from heaven"
that causes their demise (Rev 20:9).