Any nails. You should always see nails on a hip truss. People(roofers) can say they snap chalk lines all they want, but trusses are not straight when they are installed. There will always be some nails that are shiners or at least side splitters.
If you have a rafter system and hand nailed when it was framed it is possible to not see a shiner. This is usually do to the slower work speed(no guns) and the framer may have pulled any shiners.
I have had several roofs that were not re-nailed and should have been by code. We have had inspection sign-offs and roofer affidavits where I could not find a shiner or side splitter so we(HO and I) agreed to pull shingles and repair as needed, the roofers baulked. Just because they had a permit, or signed an affidavit does not mean they did what they should have. Had everyone did what they should have there would be no need for inspectors. This is why we do the inspections.