It's important to keep in mind the context about which we're speaking. Krauss is an astrophysicist. He's referring to nothing as the "cosmic soup" of virtual particles from which a big bang event could occur. In fact it may be the case that his version of nothing is the only type that can exist at all. That would mean absent all of the "stuff" that we know makes up a universe, a big bang would be inevitable. The implication that Krauss shows, is that a universe can come from nothing, no creator necessary.