I'm glad you started this thread. I have been thinking about this as well, and been meaning to take a photo with various "nude" shoes to get YLF opinion of which is the best nude for me. Because that's the thing with nude shoes: there is quite a range because everyone's skin shade is different.
I think my Cole Haan flats, which are a pearly pink, are probably the closest to my skin tone, as I do have a lot of pink/red undertones. Otherwise I have a pair of round-toe heels I think of as nude; they are kinda of... blonde? I don't know what you'd call them. I have a pair of platforms that are kind of a butterscotch too.
I think that taking into account the color of your hair is also important - that bookend effect.