As in the video,
When using the /setblock command to place a block [such as chest]
If there is the block[e.g chest] on the coordinates,
Then the nbt data in the command will not work
[The items in the chest will not be placed]

When you need to cycle through command blocks
Keep giving some novice supplies
Then
You can only use the /fill command
/setblock command does not support'replace air'