Tolkien's Hobbit, Lord of the Rings, and the Silmarillion lead directly to Perren and Gygax's minis-battles fantasy supplement, Dwarves in Chainmail (see Chainmail 3rd Ed, p. 28, and the later designer's notes article). Also, Gygax and Arneson made much use of this in the games which would later become D&D.
Tolkien claimed inspiration from the Norse and Anglo-Saxon dwarves, but admitted to changing them substantially. Terry Brooks (Shanarra Series), Poul Anderson, and several other authors specifically draw from Tolkien's presentation of the race of Dwarves.
A number of games specifically move away from Tolkien; Some make them short Norse, some make them otherwise different (like the Mostal of Glorantha, or the Shtuntee of Orkworld), and later D&D dwarves are drifted from Tolkien's model as well.
Most games follow the D&D pseudo-Tolkienian model. Most modern authors do so as well; Tolkien has been noted as stating he intended to create a saga for the English Speaking World; by most accounts, he's succeeded.
His vision of Elves, Dwarves, Hobbits/Halflings, Trolls, Orcs, and Goblins have become the English cultural norm; only Elfquest has given much challenge to this superiority, tho' the medieval English and French fairy elf views still have some traction, especially since they have much place in another still widely held cultural myth: King Arthur.
The reason that this astronomical term is used to describe a particular kind of attack comes from the "nova flame" or "nova blast" of the Fantastic Four's Johnny Storm ("The Human Torch"). This was a power that could do astounding amounts of damage in a single burst, but leave the hero spent and powerless for a time. The term was picked up and used in Champions, and then spread from superhero RPGs to other forms of gaming.
Best Answer
Trollbill1 first used the term
According to the (archived, community-made) D&D Dictionary of Terminology, it was coined during a discussion on a Wizard's message board back in 2001, by a poster called trollbill (who also wrote the post that kept the etymology on record in the link).
The beginning of that post (Honesty vs. Story) ...
1 Not sure who trollbill is, but that's the attribution and origin based on some research.
A related term, Big Bad, originated in the TV show Buffy the Vampire Slayer and likely informed the inspiration for BBEG; its usage appears to be anchored in that show's particular style.