Sugar beet production demands sustainable intensification approaches to enhance both yield and quality. This study examined the effects of foliar nano-ammonium nitrate (NH4NO3) applications on five sugar beet cultivars- JAMPOL, BTS 9830, DEL 1135, ASEEL, and Raspoly- over two growing seasons in Egypt’s Nile Delta, using a split-plot randomized complete block design. Three nano-NH4NO3 concentrations (0, 50, and 100 ppm) were sprayed twice each season to assess impacts on growth, yield, and quality parameters. The results indicated limited influence of treatments on primary yield metrics; taproot yields remained unaffected across all cultivars and seasons. Nonetheless, the 50 ppm treatment preserved optimal sugar quality, with sucrose content reaching 19.4%, compared to 18% in the controls. Carotenoid levels increased by 12% under the 100 ppm treatment, reflecting enhanced nutritional quality. Among cultivars, ASEEL yielded the best results with taproot outputs of 34 t/ha and sugar yields of 6.1 t/ha under optimal conditions, demonstrating significant cultivar-dependent variation. Multivariate analysis revealed distinct response patterns among cultivars and treatments, with three-way interactions (Season × Cultivar × Nanoparticle) affecting several traits. Clustering identified four trait groups and three treatment clusters, highlighting sugar beet’s complex response to nanoparticles. Economic analysis shows limited benefits, with no significant increase in taproot yield, despite a rise in secondary metabolites. While nano-NH4NO3 can modify biochemical parameters, the lack of yield improvements casts doubt on its economic feasibility. Cultivar choice primarily influences sugar beet performance, with environmental conditions also affecting treatment efficacy.