You would need a hell of a reducing agent and likely an alloy, i suspect the prep would be a mare and maybe after treatment. I cant think of a reducing agent off the top of my head, none of the really common ones i know of would do it.How do they do "electroless nickle" plating?
So likely something slightly exotic, may phosphites but thats guessing. Hypochlorites etc wouldnt work. Nickel is a real odd ball even for a transition metal. I will look it up in the books later and see what i come with.
Too much trouble for me, i would buy the chloride and electro plate, but i prefer electroplating. Ferric Chloride is pretty fast with catalyst (by nickel standards). Oh and some heat