“Nerve” is a lot like high school: The jocks and pretty people have all the fun before eventually being bailed out of trouble by the nerds who were ceremoniously not included. The nerd in question here is Tommy (Miles Heizer), a computer guy who pines for leading lady Vee Delmonico (Emma Roberts). Vee is blonde, beautiful and has just been accepted into CalArts. There’s no way in cinematic hell or actual Hell that she’d wind up in Tommy’s arms. Yet it’s Tommy to the rescue when Vee gets herself involved in a sinister smartphone game whose online ringmaster sounds suspiciously like Stephen Hawking.