Beer makers use DME as a 'better' sugar. I don't think it provides any of the benefits of yeast nutrient, but I have never investigated the possibility. Much yeast nutrient is DAP (Dibasic Ammonium Phosohate).
Yeast energizer would be a better replacement for YN, especially if it contains DAP.
I agree, its not a nutrient replacement, its just easier for the yeast to eat then table sugar but will add some body to your wine. Again like cp saud, energizer is better then nutrient thus the reason tou only need 1/2 of what you need when adding nutrient. In a pinch you could use a dissolved B Complex vitamin.