This third of three volumes includes papers from the second series of NODYCON, which was held virtually in February of 2021. The conference papers reflect a broad coverage of topics in nonlinear dynamics, ranging from  traditional  topics from  established streams of research to those from  relatively unexplored and emerging venues of research. These include -         Complex dynamics of COVID-19: modeling, prediction and control -         Nonlinear phenomena  in bio-systems and eco-systems   -         Energy harvesting   -         MEMS/NEMS           -         Multifunctional structures, materials and metamaterials -         Nonlinear waves     -         Chaotic systems, stochasticity, and uncertainty