The footage was uploaded on Saturday by the North's official website, Uriminzokkiri, which distributes news and propaganda from the state media.
The video is shot as a dream sequence, with a young man seeing himself on board a North Korean space shuttle launched into orbit by the same type of rocket Pyongyang successfully tested last December.
As the shuttle circles the globe - to the tune of "We Are the World" - the video zooms in on countries below, including a joyfully re-unified Korea.
The focus then switches to a city - shrouded in the US flag - under apparent missile attack with its skyscrapers, including what appears to be the Empire State Building, either on fire or in ruins.
"Somewhere in the United States, black clouds of smoke are billowing," runs the caption across the screen.
"It seems that the nest of wickedness is ablaze with the fire started by itself," it added.
The video ends with the young man concluding that his dream will "surely come true".
"Despite all kinds of attempts by imperialists to isolate and crush us ... never will anyone be able to stop the people marching toward a final victory," it said.
The North is expected to conduct its nuclear test as a defiant response to UN sanctions imposed after its December rocket launch.