We don't have synonyms for nisei yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are nisi, niser and nishi.
"1999: Decrypts fly out of a line printer on the other end and are taken off to another hut where American nisei, and some white men trained in Nipponese, translate them. -- Neal Stephenson, Cryptonomicon"
"1999: Decrypts fly out of a line printer on the other end and are taken off to another hut where American nisei, and some white men trained in Nipponese, translate them. -- Neal Stephenson, Cryptonomicon"