Sea-level rise and declining sediment supply are increasing the vulnerability of coastal wetlands, threatening their capacity to provide natural coastal protection and ecosystem services. Nature-based restoration has emerged as an important adaptation strategy for enhancing coastal resilience, yet its effectiveness under future environmental change remains poorly understood. This study focuses on the Hangzhou Bay–Zhoushan coastal system, where sediment supply has declined substantially because of reduced sediment discharge from the Yangtze River. A two-dimensional hydro-morphodynamic model will be developed to investigate coastal wetland evolution under different restoration scenarios. Three key drivers are considered: regional sediment supply, local relative tidal elevation under sea-level rise, and internal tidal creek connectivity. Changes in wetland area, sediment deposition, and geomorphological evolution will be quantified under different scenarios. The study aims to identify the critical thresholds of sediment supply and sea-level rise beyond which nature-based restoration becomes ineffective and to establish a multi-scale physical framework linking upstream sediment reduction to coastal wetland restoration. The findings are expected to provide scientific support for designing climate-resilient nature-based restoration strategies in sediment-limited estuarine and coastal environments.