Robin2:
Don't be silly - 1nHz is one cycle every 31 years eight and-a-half months.
It's not a crystal you need, it's a calendar.It took me a while before the laugh emerged
In any case to get a calculated time measured to +/- 1 nS I reckon you would need a 4GHz or maybe 10GHz clock. Almost certainly the OP can't afford the oscilloscope that would allow him to verify his timing.
...R
nS is not nanoseconds, it is nanosiemens. That doesn't need a calendar, it needs a family planning clinic.