sending nukes into an enemy hive is never a bad thing.
you send it at a colony or many nukes and many colonys
and don't bother jamming there radar if your shooting at there hive
Sending nukes at there hive is a good idea because it forces them to use ion cannon (200E). and when your alliance sends over 20 nukes at there colony's its even better because they can't ion that many(most of the time) and thay lose workers
Also when on defense nukes can be very useful for shooting at gates.
Why? because if you shoot it at there only gate in forward teritory then they are forced to ion it or lose a importent jump point(although if you don't keep there forward gate jammed then you are kinda not smart)
And if thay are massing there troops on that gate and you shoot about 8 at it most likely 4 or 5 will hit and the active players would have moved off but the slightly inactive would take losses (10% of there army for every nuke)