I suspect that might be a coincidence - the Gaelic name for Loch Ness is Loch Nis with the origins of the "Nis" being a bit unclear. Neither Loch Ness, River Ness or Inverness seem very peninsula like - although Caithness does use 'ness' in that sense but it was under Norse control for a long time but it is a broad peninsula...
That is, a peninsula that birds live on.