All the nectars I have seen in stores, some organic and some not, have had fruit juice with added water and sugar, but slightly thicker than regular juice cocktails. I think they had some fruit puree as the thickener. If anyone actually produces a product purely of actual flower nectar, I don't think I've seen it.

This link shows "the term 'nectar' is generally accepted as the common or usual name in the U.S. and in international trade for a diluted juice beverage that contains fruit juice or puree, water, and may contain sweeteners".