it should be possible to use HCl with a nitrate salt such as KNO3, however for making nanogold solutions i think you would wanna avoid adding salts. its dissolved with nitrosyl chloride, which is formed when mixing 3 parts HCl with 1 part HNO3, molar ratio. but typically you would be left with a bit of acid in this mixture that you would then have to evaporate out, my gold chloride solution has a bit of acids left and it doesnt seem to bother gold nanoparticles as its diluted down quite a lot
i know that bleach is used for gold recovery, NOCl is used because it has chlorine and oxygen, bleach is NaClO, it also has chlorine and oxygen. it might be possible, but then again you would end up contaminating it with salt in which im unsure if you could remove using solvents to remove from solution
as the amounts are quite small if you feel adventurous you could try to distill a bit of nitric acid yourself with sulfuric acid and a nitrate salt, aluminium is resistant to nitric acid but not nitrous oxides, this is first an issue once you produce +68% nitric acid however. someone with access to aluminium welding equipment could make a nitric acid distillation apparatus if an excess of nitrate salt was mixed throughly with sulfuric acid and then doused with water to have low concentration nitric acid, no nitrous oxides and the equipment lasting forever.
careful heating and a regular glass bottle is also possible, but warm acids splashing around is never great news, silicone can work for distilling concentrated nitric acids so it should hold up to low concentrations of nitric acid, this is my exhaustive take on how someone with no lab equipment could go about making proper gold chloride.
i might add DiChloroMethane (methylene chloride) can dissolve concentrated nitric acid, so it can be used to extract it and then simply evaporate off the DCM to be left with highly pure nitric acid, unsure if this works with lower concentrations of nitric acid. it can be found as PVC solvent/glue and isnt flammable, it smells great, but isnt really healthy.
now if anyone here are really feeling this adventurous, then you probably already have access to some great quality colloidal gold, anyhow thats my 2 cents and theyre free today.