Biostimulants contribute to the physiological growth of plants by enhancing the quality characteristics of fruit without harming the environment. In addition, biostimulants applied to plants strengthen nutritional efficiency, abiotic stress tolerance, and fruit biochemical traits. This research aimed to elucidate the effects on the growth, physiology, and quality of Chardonnay grapevine plants and fruits under the conventional cultivation and biostimulant (nano-products) formulation. Plants were subjected to different treatments during the whole cultivation period of the grapes (April to October) in Northern Greece (Drama-Adriani, Lazaridis Domain) under natural environmental conditions. Measurements such as mass, color, texture, and consistency (fruits) were performed on the fruits that had ripened on the grapevine, while chlorophyll fluorescence measurements were performed on the foliage at harvest. Chlorophyll fluorescence indices measured by IRGA and Imaging PAM revealed the highest photosynthetic efficiency of plants treated with biostimulants. Beneficial effects were also observed under the application of biostimulants in the maintenance of flesh consistency, ascorbic acid concentration, and phenols. In conclusion, the application of innovative nano-products serving as biostimulants is a sustainable tool to improve productivity, which aligns well with the strategy of the European Green Deal.