The bomb we dropped on Hiroshima was 14.5 kt.
So the NK bomb seems to have been at most 3-4% as powerful as the USA's very first weapon deployed.
The very first test bomb the USA conducted in NM, "The Gadget", was 18kt.
I can't find good footage online of China's first nuclear bomb test.
There is a clip on Youtube (I think sourced from the people who compiled videotapes of many of the atomic tests around the world).
My problem with their video is that they took what was a seized Chinese Communist Propaganda film (which was duplicated and dubbed for American viewing) and recut it and overdubbed it with new sound effects and monumenal music.
The other film may have been campy, but that was as the Chinese Communists MADE it. Okay, so the American narrator was LESS than enthusiastic as he read lines honoring Mao and China's greatness, it still got the point across.
THAT version of the Chinese nuke film was released (in the 1980s or 1990s) to VHS by Rhino (pre-Warner Bros. days) as "Mao's Little Red Video".
A 1 kiloton bomb can fit on the tip of the medium range missiles Kim has been firing over Japan. A 15 kiloton bomb barely fits in a WWII B-29 bomber.
The only possibly good news is that the PRK bomb was supposed to be a 15 kiloton device, but it "fizzled" at less than a kiloton.
See Tom Clancy's The Sum of All Fears.