Abstract: Core-collapse supernovae are one of the most fascinating phenomena in astrophysics but the explosion mechanism is not clearly understood yet because of their intricacies. I will give an overview about the role of nuclei and nuclear physics uncertainties in supernovae. I will also discuss key nuclei and their key information to be investigated for further supernova study, and introduce recent progress of the research on Equations of state for astrophysical simulations.