It is likely that "NBUAC" is an acronym rather than a traditional word, making its spelling unconventional. However, using IPA (International Phonetic Alphabet), we can represent the sounds in the acronym as /ɛn.bi.ju.eɪ.si/, where "en" represents the "N" sound, "bi" represents the "B" and "U," "ju" represents the "A," and "eɪ" represents the "C." While there isn't a standardized spelling of acronyms, using IPA can help provide a clear representation of their sounds.