The British actor's character is a member of The Toxic Mega-C***s, a gang led by the movie's primary antagonist Red Mist.
Nyman has previously appeared in the films Dead Babies and Severance, as well as the E4 horror satire Dead Set.
Directed by Jeff Wadlow, Kick-Ass 2 sees Aaron Johnson, Chloe Grace Moretz, Christopher Mintz-Plasse and Nicolas Cage reprise their roles from the previous film.
Series newcomers include Morris Chestnut, Robert Emms, Donald Faison and John Leguizamo. Jim Carrey and Lindy Booth are understood to be in line for supporting roles.
Kick-Ass 2 will be released on June 28, 2013 in the US, with a UK release date yet to be set.
Watch a trailer for Kick-Ass below: