Well, yeah, but if you give an English speaker "Natzi", he pronounces the "a" like in "hat", and it comes off sounding like "Nätzi"...
...Whereas the "o" in "not" sounds pretty much like the German "a".
But try and describe to an English speaker what an "ü" or a "y" should sound like, let alone "ch"! And German is one of the simplest languages to pronounce... The English discrepancy between spelling and pronunciation seems to hobble people in that respect.
(Then again, the speakers of simply pronounced languages are sometimes at a disadvantage, too. I'm constantly surprised by how for example Arabs never need to struggle with the weirdest European names, having such a broad selection of native sounds to choose from that they can effortlessly pronounce Finnish or Gaelic names alike, then write them down so that a fellow Arab can repeat the flawless pronunciation without ever having heard it.)
Timo Saloniemi