Interesting. A thing I had heard over the years is that noses were kind of phallic (which seems pretty obvious), so if you were interested in a symbolic neutering, taking the nose off was both physically simple to do and symbolically potent.
I'm not sure that the obviousness of this kind could be trusted. The idea of "phallic" was popularized by Freud. It is understandable that we are now have phallic symbols and see them in any prolonged object, either it is because of our nature, or it is because Freud made us to see them. But I'd rather not to apply this very idea to people of ancient Egypt. Or at least I wouldn't trust it's obviousness. Obvious is no…
anachronistic thinking is an ever-lurking danger, though, which is why i'm not amazingly confident in this interpretation, but brought it up out of curiosity.
We do know that body-part substitutions were at least in literary use in the ancient near east, so it's not totally implausible: you can fairly confidently swap foot/thigh for genitalia in ancient hebrew texts, when contextually appropriate.