In his work Tom Sealy discovered swarming bees have a set of preferences for their new home, rather like the filters we might apply when looking for a new home on RightMove. He found the volume of the nest site ideally needed to be ~40l or more. This happens to be the size of the Langstroth as used in USA. A National brood box is ~35l so just about ok. A nuc would be considered too small and in my experience they are too small for housing a decent size collected swarm.
I have a 6 frame nuc which also has a super. For a few years it was outside my workshop and it caught a swarm at least once every year!!! I shouldn’t have moved it! I guess being that little bit wider and with a super too, it made it a good size.
One year, whilst Dave Peckham was with me, a swarm came inside my workshop and hived itself on the top shelf of some metal racking upon which was a super. Quite a sight and very funny as my son Jack was in there working in his car and he hates bees!! Bless them, you never really know what they will do….