For spices, I asked in a specialist spice shop & they said the best thing to use was a stone (specifically granite) mortar & pestle, which I already own. TBH spices & nuts are pretty different in size & texture, so you'd probably be best using something sifferent for them. Plus, you really want something you can fully disassemble & wash after grinding nuts in it - not ideal for a spice grinder as they can go rusty I believe. Some people use a coffee grinder & use it exclusively for spices, if that's the sort of thing you wanted?