Cities have always been places that generate problems, but also places where solutions are born. In recent years, cities have become a testing ground for finding and testing solutions to overcome the climate crisis. The subject of the paper is Nature-based Solutions (NbSs) that strengthen the resilience to climate change, influence urban spaces, and improve the quality of life of residents. The study focusses on the identification of NbSs, the diagnosis of its participation in local adaptation activities, and a comparative analysis of the activities planned and implemented in 44 large Polish cities in 2017–2023. The authors analyse data from 44 Polish cities, based on the types of NbSs implemented in European cities that carried out the URBAN GreenUP project. The results of the study show that Polish cities, while introducing sustainable urban lifestyles through NbSs, do not take advantage of all the opportunities inherent in these solutions. They focus on greening urban spaces and implement water interventions and singular green infrastructure measures to a lesser extent. There is negligible use of innovative and energy-using activities. The quantitative data obtained can be used to identify the gaps and potentials in the use of nature-based solutions in the adaptation of Polish cities to climate change and energy transformation. The aim of this work is also to identify recommendations to incorporate NbSs into urban adaptation policies in Poland. The authors conclude that the research conducted can serve to improve the knowledge on the links between NbS planning in adaptation activities and their implementation in urban spaces. An awareness of NbS gaps can influence the intensification of research on the implementation of innovative adaptation solutions, including energy-based solutions. The results obtained can also contribute to a better organisation of urban policies that aim to increase the resilience of cities to climate change.