*nes-

The core of this root was the idea of:

returning home safely

But it soon broadened to include ideas that are about the general sense of well being, like health or healing, as we can see in the German word genesen.
And in German, it also included the idea of nutrition, which as any health coach will tell you is an essential part of our well being.

In English, we find the root in the word nostalgic which in a way is a yearning for returning “home”. And it’s also in the second part of harness, which originally meant provisions (food) for the soldier.