In Age of Ultron, Iron man called the Hulk Buster program Veronica.
Why is it named like this, is it some kind of reference to Archie comics or is it straight from Marvel comics?
"Is it some kind of reference to Archie comics?" Indeed. From Comicbook.com:
When asked why that was the case, [the film's writer and director, Joss] Whedon explained that it tied back to Bruce Banner's own personal backstory. More particularly, to Betty Ross, Hulk's love interest in his solo movies and the comics.
"You know, I just decided to call it Veronica because he used to be in love with a girl named Betty and Veronica is the opposite of that," Whedon said, obviously referencing Betty and Veronica, who compete for Archie Andrews' attentions in Archie.
(The quote comes from an Age of Ultron press conference.)
This has no part in the comics, but a "veronica" is a move in bullfighting. (Free Dictionary: A maneuver in bullfighting in which the matador stands with both feet fixed in position and swings the cape slowly away from the charging bull.) It's interesting that Whedon picked a name that also has significance in a "man vs. beast" type of conflict, and not a move in which the bull is killed but is being teased or distracted.
The name Veronica could also have a certain significance for Tony Stark. Veronica Benning becomes the physical therapist for Tony Stark after he comes out of cryogenic suspension in the comics. Things get personal between the two when Veronica reveals her affection towards Tony Stark. She appears in "The Invincible Iron Man", "Force Works" and "Iron Man: The Ultimate Guide to the Armored Super Hero" comics.