Yes, you can add a yeast nutrient to the honey water mixture for a mead. The sugars in honey don’t feed yeast like the sugars in malts that are used in beer do. A yeast nutrient is a natural food for the yeast and gives nourishment to the yeast so that it stays healthy throughout the fermentation process. Use it in beer, wine, mead, etc. to produce healthy yeast for a complete fermentation.
My summer brew yeast scoffs at yeast nutrients and eats and (asexually) procreates at a rapid rate, outgassing CO2, and excreting H2C6O.
Alien civiliations will wonder why we are concerned with the excretions of budding single celled organisms, and the facination they hold for us mere human mortals. ;)
/johnny