Learn English – What does “Nothing doing as he took it right to him” mean

To be nothing like means it is completely different and has nothing in common. Nothing like anything means incomparable; completely different from all other things. This is the literal meaning of the term, no figurative or idiom involved.

There are three examples of nothing like anything in the Corpus of Contemporary American English (COCA):

it was just an unbelievable event and nothing like anything the country had ever gone through before

Here the speaker means the event was completely unlike any event previously experienced in the country.

" It seems like I've always had some type of adversity, " Bobby says. " My freshman year at Duke, we lost the title game by 30 to UNLV.... But this is big adversity, nothing like anything else. # "

Here the speaker is referring to some type of adversity that this time has a magnitude never before seen, incomparable to any previous adversity.

" She spun around, drinking in the scenery, marveling at its almost palpable presence. " But... this is nothing like anything I've ever seen on the' net! "

Here, whatever it is the speaker is experiencing is unlike any experience she has had in the same environment.

This usage of "if nothing else" is idiomatic, as D_Bye pointed out. In your example "... automated scanning, which every e-mail provider does, for security purposes if nothing else.", you could replace it with "if for no other purpose". It means that e-mail providers feel that security purposes are enough reason for scanning e-mails: they would scan e-mails for that reason alone anyway, so it doesn't really matter whether scanning could be justified based on other reasons.

A: Should I take some money from the company's cash box? Any reason not to?

B: Huh? What!? You might consider the possibility of getting caught, if nothing else [ = if you will consider nothing else].

B means that if A won't consider other reasons, such as the moral obligation not to steal, at least she should consider that she may get caught.