Climate change, extreme weather events, and anthropogenic activity pose a serious threat to agriculture and crop productivity. In addition to these, heatwaves, droughts, floods, persistence of leftover pesticide particles, the buildup of heavy metals, and pollution with harmful organic residues negatively influenced the agricultural environment. Additional clues need to be taken in order adapt and protect the agricultural systems against such combination events guarantee food supply security. Thus, it is a current need to ensure global food security. The conventional methods are not adequate enough to overcome such challenges. Hence, alternative approaches are required on an urgent basis. Application of chemical nanosensors could be a long lasting solution towards sustainable agriculture for their accuracy, real-time data on different environmental parameters and crop health indicators, which presents an inventive solution to these problems. These nanosensors possess the capacity to greatly raise the yields of crops, lessen environmental impact, and manage resources more effectively. This chapter aims to discuss various recent applications of chemical nanosensors in sustainable agriculture such as checking the soil health, monitoring the change in soils’ pH, soil moisture content, and nutrient levels of the soil, detecting of pollutants and heavy metals, as well as identification of plant diseases. Thus, Smart farming prevents overuse and minimizes runoff that can cause environmental degradation, so in addition to increasing productivity, it also ensures sustainability.