Nickel chloride from Nickel oxide

Hello, this is my first post on this forum and if i make some mistake hope you wont be harsh (btw sorry for my poor English)

I live in country where it is really hard to get some chemicals (some concentrated acids, some carbonates, some metals.. )

I need Nickel chloride (no need for anhydrous, hexahydrate is ok) so i bought Nickel oxide, black one, Ni2O3. I know there are two different Nickel oxide, green one NiO and black one Ni2O3 (mine is brown / black, cant say it is pure black)

Ni2O3 + HCl = NiCl2 + H20

Problem is when i put some nickel oxide in HCl (16 - 18% cause in my country concentrated acids are not so easy to obtain) green color of NiCl2 didnt appeared. So i have to work with ~ 15% concentrated acid only way i saw in that moment is to boil it and hope for some reaction to occur. So i did, i boiled it shortly, ofcourse on open and green color appeared. I still smell strong hcl and i put some ph paper which showed me high acid.

Question is how can i know if i rly made some nickel chloride and if i did how to seperate it and crystalize cause i need it solid (hexahydrate) ?

I can heat it and try to evaporate but i dont know if nickel chloride will stay in beaker or neutralize acid with some base (sodium carbonate / bicarobante solution maybe or sodium hydroxide) but i am afraid it can affect nickel chloride and i left with nickel hydroxide which i dont need...