I 2005 nissan navara outlaw, there are 79500 miles on it, at how many miles does the timing chain need serviced or changed?

It is usually the timing chain tensioner that malfunctions. However if you have a timing BELT it should be replaced between 75-80k miles.

A chain driven system will typically outlast the engine itself if everything is in a good order.

However there was a recall on some frontier engine's timing parts, you may want to have your VIN checked at a local dealer to ensure your engine doesn't qualify for the TSB repair.