What are the uses of nipa palm sap?

Answer 1

The sap of Nypa fruticans is used to produce a brown sugar, called gula melaka, to fermentate it to a liquor or vinegar.

And to feed pigs:
In the Indonesian islands of Roti and Savu, the sap tapped from the palm is fed to pigs instead, allowing the pigs to fatten during the dry season when other fodder is scarce. The pigs are also fed the leftovers after sugar preparation. In this way, the Nipah Palm results in protein for the community.

The Nipah palms produce large quantities of a sugar-rich sap that can be used for ethanol production.

Answer 2

Apparently it's used to make an alcoholic drink: http://en.wikipedia.org/wiki/Nipa_palm