Arizona city nicknamed "The Old Pueblo" (6)
I believe the answer is:
tucson
'arizona city nicknamed the old pueblo' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tucson that I've seen before include "City in 9" , "Arizona city that counts badly" , "American city" , "US city" , "Arizonan city" .)