This post is based mostly on Krauss's comments in the interview by Rogan:
https://www.youtube.com/watch?v=bDhHK8nk_V0

It is a lengthy interview with too much to comment on in one post so I will make my comments in numerous posts with references to the time in the video so interested readers can quickly find that spot.

1.
Before i get to the universe from nothing tale by Krauss, I'd like to note that Krauss is a higher level thinker compared to Dawkins. Krauss stated, "I use the word belief all the time but I try not to OK...." (Min 55+) and "if you really want to think of rational inquiry of course we all have beliefs which means we have preconceptions....". That insight, namely, "we all have belief's which means we all have preconceptions" Is a sign of a higher quality thinker. I don't recall Dawkins making such a quality statement. Apparently Dawkins, and many of his followers are oblivious to preconceptions or beliefs. (Additional terms for beliefs and preconceptions are presupposition, pre-scientific beliefs, assumptions, premise and the like.
2.
One preconception of atheists is simply stating disbelief in God. Its a metaphysical unfalsifiable perspective. For example, disbelief in a Creator God implies that the only thing that exists is nature. In turn that implies that if nature had a beginning, it had a natural beginning. That too is a metaphysical belief or preconception. Alternatively, if nature didn't have a beginning, the implication of atheism is that it always existed.
3.
Burden of proof: Atheists apparently make a big deal over the burden of proof. But Krauss, to his credit, clearly states he can't prove his origin of the universe tale. yet, apparently, he believes it. Nothing wrong with that. Now, does he have the burden of proof for some stance that is already clearly unprovable? There is a serious problem with the atheist "burden of proof" concept. If something is already unprovalbe, it makes no sense to demand proof. it is simply a belief, a preconception, a presupposition, a pre-scientific belief. Same thing with theism: if it is unproveable it is ridiculous to demand proof.
4.
Preconceptions and evidence. Atheists seem to be obsessed with "evidence". But what comes before "evidence" is your/our preconceptions. We all think and see from within a set of personal preconceptions. Our personal preconceptions define the parameters of what we think and see. For example, a person with atheist preconceptions will not see God nor see evidence for God be cause they have already assumed God does not exist. it doesn't make sense to claim there is no evidence for God after one already assumes God does not exist.
5.
Given Krauss's (atheist) preconceptions his only options concerning the origin of Nature is a) it always existed, or b) it created itself from nothing. Apparently, based on the title of his book:

https://www.google.ca/search?q=how+the+universe+came+from+nothing+Krauss...

he subjectively picks the universe created itself from nothing. I suppose if he picked 'it always existed' he'd have trouble explaining the big bang, the apparent beginning of the universe some 13.8 billion years ago.

6.
Krauss's origin tale is this: prior to the big bang, prior to nature and space-time existing there was nothing. But nothing was really something, namely, quantum fluctuations. Then, this nothing which is really something burped and the universe popped into existence. (video reference - 2:11+) Is this falsifiable? No. Is it verifiable in any way. No. Does Krauss say he can prove it? No. he said he can't prove it. so what is it? It a part of his assumptions, his preconceptions, his presuppositions, his pre-scientific beliefs. Its part of the conceptual framework from which he thinks and sees. That assumed conceptual framework defines the parameters of what he will think and see.
7.
His origin tale, his science fiction yarn, has some problems. How does he get that nothing is something? And why does he declare that nothing is something? I got some help from a six year old arithmetic whiz. I asked her what is zero? She said its nothing. How many ones are in zero, I asked. None, she said. How many twos in zero? None silly, zero is nothing. So, according to her, you can't get something from nothing. So the universe can't come from nothing. Krauss's origin statement is then missing a word, namely, abracadabra. His statement should go like this: nothing is really abracadabra something. Obviously magical thinking. Then, abracadabra, the something that is nothing burped and abracadabra the universe popped into existence. This si-fi yarn is a Leprechaun in Krauss's basement that he apparently insists is plausible, and apparently believes in. But I don't find it anymore credible than some ancient origin myth. so what made him create this myth? Otherwise, he said, you might need a deity. Clearly, he created an atheist origin myth for philosophical purposes.

I have more comments on various topics made in the video, but they will come in later posts, other wise this already long post will be unmanageable.