At this point I like to control the placement, because this can help guide me when I later decide to change individual cubes, if necessary. Head to the NanoMesh menu and click Alignment. Change this to Align to Normal, then use the Random Distribution slider to adjust the position on the fly.
Even though the cubes are the same, the distribution is improving things already. Randomise the cubes for a more believable appearance. Changing the Alignment helps to keep things looking more real.