The full run of the journal is online. The journal slightly changed its name to Journal of the Ganganatha Jha Kendriya Sanskrit Vidyapeethawith v. 27, parts 1/2 (Jan./Apr., 1971). The volume you are looking for is at https://csu-prayagraj.res.in/pdf/29%20XXIXJan-JUNE-1973%20PART%201-4.pdf#toolbar=0 and the Nakamura article starts on p. 367.

All the best,

Dan