Healthy ecosystems, and their associated services, can provide effective natural protection against water-related climate risks. Nature-based solutions (NbS) have recently gained momentum in international policy discussions due to their potential to foster synergies between ecosystem health and human wellbeing, while also offering economic benefits. This paper provides an overview of the use of NbS to date in OECD countries and finds that in most cases ambition for NbS does not match practice. Focusing on the application of NbS for addressing climate-related flood and drought risks, this paper explores why prevailing decision making frameworks may fail to adequately consider NbS. It sets out a policy evaluation framework that supports the identification of, and proposed ways to address constraints on the use of NbS to address water-related climate risks.