Technically, a "nova" today would be a very special phenomenon only applicable to white dwarf stars (and perhaps black holes) that have a companion star or other source of extra mass. The "Return to Tomorrow" phenomenon would not meet the current specs of what qualifies as a nova.
However, "nova" originally was a generic name for unexplained phenomena seen from afar and involving a star exploding into great brightness. Just because we today can explain what happens at those faraway stars to cause the phenomena we once classified under "nova" should not as such be grounds for limiting the use of "nova" to only those specific phenomena. The terminology of science is wrought with illogic anyway; here at least future mankind might have taken a few corrective steps and re-established "nova" as "like supernova, but smaller" (and perhaps also introduced things like "micronova"). These would encompass all the mechanisms capable of producing the big bang in question, and merely divide them into categories of magnitude of observed effect.
Who knows, perhaps "supernova" in the 23rd century is reserved for stellar explosions big enough to endanger the entire galaxy, while "nova" covers the things previously known as supernovae?