So yeah - Taco Bell, Taco Time, Del Taco, Costa Vida, Cafe Rio, etc., all count as Mexican in my book - and Panda Express, along with any other random Chinese food place around here, counts as Chinese.
I'm not sure how to look at it otherwise.
I mean - if all of those places above are considered "American" because they are Americanized versions of the original, that would be my pick for favorite all day long. Not because I don't like authentic too - but because it would make an immensely broad variety.