Question about nanoseconds

Are nanoseconds guaranteed to increment chronologically? For example:

 1603223987294927587 (nanosecond timestamp from Polygon)

 which is -> Tuesday, October 20, 2020 12:59:47.294 PM GMT-07:00 DST

If I do:

if otherNanoSecondTimeStamp > 1603223987294927587

Would that guarantee that otherNanoSecondTimeStamp happened AFTER the timestamp mentioned above?

Use case

I am coding a backtester that requires all trades and quotes in chronological order. I pull both of them and basically have 2 lists: allTrades & allQuotes and I want to create 3rd list that has all of them sorted in order of time execution. Maybe there is a better way to do this? Thanks for reading.