In my setting, there is a ban on nuclear detonations greater than one kiloton in magnitude. This ban is enforced with a supranationally controlled strategic nuclear arsenal capable of essentially annihilating a country; one North Korea-esque nation violated it while being invaded by their equivalent of South Korea (read: nuked their capital city with a 635-kiloton boosted fission weapon) and was promptly wiped off the map.
As one might imagine, the folks in this setting are less concerned with the radiological effects, death toll, and proliferation risks of nuclear weapons then we are in real life. This means that sub-kiloton weapons are often used in warfare, primarily against tanks (two hundred+ ton, nuke-resistant abominations), against hardened positions (usually undergrounded or armored with a half-meter of lead), against aircraft (lots of anti-flash white), and during naval warfare (countermeasures up the wazoo, from nuclear depth charges to fission reactor-powered laser point defense systems).
The problem with Davy Crockett-sized nuclear (fission, of course; these are much too small to be fusion bombs) munitions flying everywhere is that you have to build a lot of them. So, this begs the questions:
How quickly and in what volumes can sub-kiloton nuclear bombs be manufactured, assuming a 21st-century industrial base and adequate knowledge of how to construct them?
Are there any production bottlenecks besides the supply of fissile elements?