Treating wasp nests won't necessarily help and may make things much worse if not done correctly.
If the nest you are referring to is really busy with high volume of forager traffic it probably means the nest is still in the hunting phase. If the wasps attacking your nucs are going after honey then the nest is unlikely to be the culprit. If however, the attacking wasps are going after brood or the bees themselves for protein then it very well may be.
If you use pesticide at the sentry point to the nest during daylight hours, i.e. after the foragers have starting flying, you risk converting hunting wasps into sweet feeding wasps which will simply add pressure on your hives. Treating the sentry point incapacitates the sentries which has the effect of removing landing rights for the returning foragers so they don't all enter the nest and don't all die. It does mean that wasps that would otherwise be fed sugars regurgitated by the grubs in their nest are denied their sweet food source so will be forced to convert to sweet feeding, i.e. potentially start attacking your hives.
If you need to treat a nest, the best way is either vacuuming because with this method you are eliminating foragers which means they can't then morph into sweet feeding wasps or if using pesticide then at night using a foam to seal the nest entrance(s) directly (not the sentry point) with a fatal dose then injected directly into the centre of the nest.