I am not familiar with Krauss and so do not know if he is making this error, but when people do make the error that sounds like this, what they usually are doing is equating the nothing from which we say God created the universe with some sort of thing in an already existing reality.
Science does a pretty good job explaining (and is improving its explanations all the time) what the universe looked like in the past, and how it got from what it looked like then to what it looked like now. But it cannot answer the question “why is there something rather than nothing,” because all causes that it can find are things (this includes laws of physics - a universe with no matter and even no energy but with laws that would cause them to appear is not nothing). No thing can be the reason for why it is false that there are no things, because, in the hypothetical model where there is absolutely nothing, that thing is not there to cause there to be things and hence show a contradiction. That is, the statements “the existence of X causes things” and “there are no things” (which includes no X) are consistent, because it doesn’t matter what X would do if it did exist if it does not exist.
(To preempt a common response, yes God is originally postulated as a first cause which must exist if things exist, but reasoning from then on shows that He is not a thing, and ascribes several attributes to Him that both cannot apply to any physical object or mere law of nature or whatever and that must apply to this non-thing first cause - hence ruling out the sorts of claims that the universe itself or some law therein is the non thing that causes things.)
