the test for choride is silver.
NH4CL = AGNO3 ---> AgCl(solid white) + NH4NO3
if enough silver will precipitate the chloride.
this WILL NOT remove the ammonium cation from your nitric acid,
if distilling most ammonium I believe will form ammonium sulfate, and stay behind in boiling vessel,( but I think some NH4 or NH3 will carryover)
it is the NH4, NH3, ammonia that I would be concerned about, not the chloride with silver or other metals.
silver is soluble in ammonia (CAUTION DRY EXPLOSIVE FUMILATE) in proper preportion.
this is why we normally do not use, or promote the use of ammonium nitrate fertilyzer for making nitric acid,
this is something that I can only theorize on from what I understand of it, and can only give answers as my limited education allows, these are also some of the things I have puzzled over.
my suggestion use another fertilizer to make poormans nitric,
or do not let solutions dry out with silver ect.
or get more answers on the chemistry of this.