What would be called Tex-Mex in America is called Mexican in Australia and would usually not be associated with America.
I think there's a Hooters in Parramatta although I don't usually venture that far west.
There's a Tony Roma's too which would also classify as American. Personally I think "American" food is probably too heavy and rich to ever be considered anything but fast food over here.
Australia is much like the United States in that a lot of the food we do well is not from Australia, like Thai and Vietnamese. I guess the same is true of British cuisine and Indian.
Although I could go a shrimp poboy right about now.