I have two pieces of advice. Always ask yourself how you know they are queenless, and second, replace like for like. That is, if they expect a mated queen, give them one; if they expect a virgin, give them one; if they expect a cell...
These principles can be ignored, but that's when you make things difficult and decrease your chances of success. If you have no alternative, roll the dice.
i got two late queens end of march
one went into a queenless hive between two frames of open brood i had taken from another hive.
the other went into a weak hive after i squashed the queen.
i noticed that the weak hive was getting lots of attention from the other hives but no robbing frenzy and i had reduced the entrances.
i saw a handful of dead bees out the front one day so i lifted the two box hive and it was obviously empty.
i opened it up and there was a carpet of dead bees on the floor and a dead queen and a handful of bees.
i think it had starved.
it took about 10 days to go from two boxes full of honey to empty with stealth robbing.
so keep an eye on your nuc at this time of yr.
Probably a bit late to say so now i only just seen this thread. But if a mated queen is put into a hive with uncapped queen cells, very often the bees will destroy those cells. But if a mated queen is introduced to a hive with capped queen cells, it is a toss up wether the bees will destroy those cells or not. Sometimes they will go on to hatch, and when they do they are quite capable of killing the mated queen you introduced.
Rule of thumb should be always destroy all queen cells before introducing a mated queen. Also check to see they have not hatched already, if they have you need to hunt down the virgin/s.