The three NIMS guiding principles are flexibility in adapting to diverse emergencies, scalability in managing incidents of all sizes, and interoperability in ensuring seamless collaboration. Flexibility involves leveraging IMTs, EOCs, and ERPs. Scalability encompasses the use of NIMS, ICS, SOPs, and Mutual Aid Agreements. Interoperability emphasizes Common Terminology, Standardized Communications Protocols, Joint Training Programs, and Interoperable Technologies.