<p>Nanohydrogels, as hydrophilic three-dimensional (3D) polymers on the nanoscale, maintain their structural integrity and can retain large amounts of water. Furthermore, nanohydrogels offer notable advantages over traditional drug delivery methods. Their inherent biocompatibility and ability to fine-tune their physicochemical properties make them ideal candidates for targeted therapeutic delivery. Incorporating stimuli-responsive components allows for precise control and targeting of drug release, significantly reducing off-target side effects, enhancing therapeutic efficacy, and ultimately improving patient outcomes. This targeted approach is preferable to conventional techniques, where systemic drug administration often causes adverse side effects due to interactions with healthy tissue. Smart nanohydrogels aim to provide a more accurate and effective means of delivering therapeutic agents directly to specific sites. This review concentrates on current advances in intelligent nanohydrogels for drug delivery, including different types, design strategies, functions, drug delivery applications, and mechanisms, with a particular focus on cancer treatment.</p>