Hi,
In my lab, my friend used a method different from yours to plating a Ni
layer on polymer film. But not trying on SiO2 or Silicon Nitride. But I
am figuring that his method should be working.
Check the paper "Electroless Nickel-Plated UV-Embossed Microstructured
Surface with Very High Aspect Ratio Channels" in Langmuir
Good luck
Samuel