I agree with MH. You can shade metallics just as well as non-mets, or can even use greys and just put a coat of metallizer medium over it. I’ve found that on smaller miniatures, like 15s human figs, there’s really no point in trying NMM as there generally isn’t enough surface area for the blending and shading to really stand out. Now, on some of those brute 35mm minis is a different story!
"I saw this in a cartoon once, but I'm pretty sure I can do it..."