Keith,
Is it a big fat nuc absolutely full of bees and brood? Queen been laying for several weeks.
I would hope so at this time of year.
The supplier could have asked if you really wanted it and offer to overwinter or refund if it's very late.
There is a legal phrase "Time is considered to be the essence of this order" Put it on the order and state a delivery date. If the order has been accepted - and I would say that receipt of payment is acceptance - and item has not been delivered by the date stated you have the right to get the same product from elsewhere and if more expensive, get the diffrence from the original supplier.
A good nuc should overwinter OK though, especially in your capable hands!
I've got 4 full nucs that are going into 8 frame boxes to overwinter. That size should do them nicely.