Nanobiotechnology, especially through biogenic and green-synthesized nanomaterials, has revolutionized strategies to enhance plant productivity and environmental sustainability. Harnessing eco-friendly synthesis routes mediated by plants, microbes, and algae, a diverse array of nanomaterials (Ag, CuO, ZnO, Fe3O4, Se, and so on) have been tailored for enhanced nutrient delivery, seed priming, and stress resilience. Nano-fertilizers loaded with essential elements (Fe, Zn, P, S) show superior uptake efficiency, reduced nutrient leaching, and improved crop vigor. Biotic and abiotic stress mitigations via nanoparticle-mediated antioxidative pathways, osmolyte regulation, and improved root architecture have been well-demonstrated in controlled studies. Meanwhile, nanocarriers and nanosensors integrate precision delivery and real-time monitoring, opening avenues for informed agronomic decision-making. However, with these advances come concerns about nanoparticle ecotoxicology, bioaccumulation, and regulatory inertia. A balanced perspective emphasizing life-cycle assessments, standardized risk evaluations, and ethical deployment schemes is essential. We examine current challenges, including field-level validation, socioeconomic equity in technology adoption, and nanoinformatics integration, and offer a forward-looking framework for sustainable and scalable nanobiotechnological interventions in plant systems.