Display omitted •Chitosan is one of the most available natural biopolymer that has been extensively studied for a wide range of applications in a green economy and sustainable frame.•A great development and integration of functional nanomaterials for the advancement of electrochemical (bio)sensors has been recorded in literature.•Chitosan functionalisation strategies and chitosan-functional nanomaterials improve the overall analytical performance of electrochemical (bio)sensors in many applications.•The modifications/functionalisation of (nano)chitosan to improve sensing capability and the technique of fabrication of chitosan-based (bio)sensors are discussed on the base of recent literature works. Chitosan (Chit) is one of the most available natural biopolymer that have been extensively studied for wide range of applications such as biomedical, drug delivery, energy, environmental remediation and food industry. In this review, we have collected and discussed research literature of recent years dealing with modification/functionalization of Chit at the nanoscale and techniques of synthesis of Chit-based materials for application in electrochemical (bio)sensors. Chit-based nanomaterials functionalization strategies and the state-of-art of their incorporation to advance electrochemical (bio)sensors in various fields of applications have been thoroughly discussed together with the most effective methods of Chit deposition (molecular imprinting, layer-by-layer, and electrodeposition) and the role of Chit in biosensing promotion.