How to measure the percent weight of NaCl in a potato chip
I'm somewhat skeptical that atomic absorption spectroscopy (AAS) would work as you outlined the procedure. The "solution" would have starches and fats floating around in it. 

(1) I'm not sure that you could get a homogeneous solution. 

As far as the homogeneous solution, think of some parts of the solution settling. So what happens if the solutions sit for an hour before going into the AAS?

You could test this by homogenizing a sample and analyzing it immediately, then analyze it after an hour. Do you get the same result? 

(2) Even if you did I'm not sure that all the gunk would burn correctly (uniformly) in the AA flame. 

Using a plasma spectrometer would solve this problem. 

(3) Depending on what sort of accuracy you want there is also the problem of moisture in the chip. How "dry" is a potato chip?

(4) There is a difference between salt added to the chip and $[\ce{Na^+}]$ and  $[\ce{Cl-}]$ in the chip. I'd guess that $[\ce{Na^+}] \approx [\ce{Cl-}]$ in a biological system, but I'm sure that it isn't exactly $[\ce{Na^+}] = [\ce{Cl-}]$. 

Such are the joys of method development in analytical chemistry.