[Legate of Amon Lanc]

Exactly. Nenya was in the first place the thing that caused Lórien not to wither; and as Sam felt it:

Originally Posted by Mirror of Galadriel

Whether they've made the land, or the land's made them, it's hard to say, if you take my meaning. It's wonderfully quiet here. Nothing seems to be going on, and nobody seems to want it to. If there's any magic about, it's right down deep, where I can't lay my hands on it, in a manner of speaking.
(...)
Yet if you succeed, then our power is diminished, and Lothlórien will fade, and the tides of Time will sweep it away.

It was also what kept its borders safe - I'd also think that for example the white mist that covered Eorl's ride to keep them secret and safe from Dol Guldur was the work of the Ring.

Originally Posted by Unfinished Tales; The Ride of Eorl

(...) but other powers also were at work. For when at last the host drew near to Dol Guldur, Eorl turned away westward for fear of the dark shadow and cloud that flowed out from it, and then he rode on within sight of Anduin. Many of the riders turned their eyes thither, half in fear and half in hope to glimpse from afar the shimmer of the Dwimordene, the perilous land that in legends of their people was said to shine like gold in the springtime. But now it seemed shrouded in a gleaming mist and to their dismay the mist passed over the river and flowed over the land before them.
Eorl did not halt. "Ride on!" he commanded. "There is no other way to take. After so long a road shall we be held back from battle by a river-mist?"
As they drew nearer they saw that the white mist was driving back the glooms of Dol Guldur, and soon they passed into it, riding slowly at first and warily; but under its canopy all things were lit with a clear and shadowless light, while to left and right they were guarded as it were by white walls of secrecy.
"The Lady of the Golden Wood is on our side, it seems ,” said Borondir.

But I don't think Nenya gifted Galadriel with much power of her own, as Boro suggested. For it was not the purpose of the Elven Rings, as Elrond says to Glóin:

Originally Posted by Council of Elrond

[The Three] were not made as weapons of war or conquest: that is not their power. Those who made them did not desire strength or domination or hoarded wealth, but understanding, making, and healing, to preserve all things unstained.