1
general::
Phrase(s): *in the (very) nick of time
Fig. just in time; at the last possible instant; just before it’s too late. (*Typically: arrive ~; get there ~; happen ~; reach something ~; save someone ~.) • The doctor arrived in the nick of time. The patient’s life was saved. • I reached the airport in the very nick of time and made my flight.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Also, just in time. At the last moment, as in The police arrived in the nick of time, or He got there just in time for dinner. The first term began life as in the nick and dates from the 1500s, when nick meant "the critical moment" (a meaning now obsolete). The second employs just in the sense of "precisely" or "closely," a usage applied to time since the 1500s. Also see IN TIME, def. 1.
American Heritage Idioms