Looks good to me but it might be man made hard to tell since its so circulated looks more like it was done intentionally.
It looks damaged to me, but if you place another nickel in the spot and it fits perfectly, I could be convinced otherwise.
Really worn from circulation but it appears to have an edge at the missing part, implying it was man-made when that part was removed, but not my field of experience.
I'm not seeing the Blakesley Effect and I see rolled over material in the affected area. I don't think this is a planchet error. Filed off perhaps.