This book constitutes the refereed proceedings of the Second International Conference on Network Simulation and Evaluation, NSE 2023, held in Shenzhen, China in November 2023. The 52 full papers presented in this two volume set were carefully reviewed and selected from 72 submissions. The papers are organized in the following topical sections: CCIS 2063: Cybersecurity Attack and Defense, Cybersecurity Future Trends, Cybersecurity Infrastructure, Cybersecurity Systems and Applications. CCIS 2064: Cybersecurity Threat Research, Design and Cybersecurity for IoT Systems, Intelligent Cyber Attack and Defense, Secure IoT Networks and Blockchain-Enabled Solutions, Test and Evaluation for Cybersecurity, Threat Detection and Defense.