An attempt to this:
Nectar is literal translation of original gurumukhi word (in Gurubani) i.e. Amrit.
Amrit stands for immortality. As Amrit = Am + Marit, Marit meaning death or mortality, whereas Amrit is for immortality. Persians literal translation is Aab-e-Hayyaat.
In Sikhism, Historically in Khande de paul (Amrit ceremony), Amrit stands for the holy water used to initiate sikhs to Khalsa brotherhood. Amrit is treated as Naam of Akaal Purukh (Ik Ong Kaar).
I understand, this answer is not complete, as the pool of nectar is still not touched on in this reply. But first of all, does this reply invokes more thoughts in you?
Best Regards.