It is not normal for a timing belt to make any noise. It is whining because something is out of place. It is either under too much tension or there is not enough lubrication.
you should never have to replace the chain. not impossible but rare that this has to ever be replaced. if it is a 2000 to 2003 model with a 3.3l v6 it has a timing belt which needs to be replaced every 105000 miles.
No problem
chain
no
Under normal conditions the timing chain will last the life of the engine. It is normally replaced during a complete engine rebuild.
Under normal circumstances the answer is no. Timing chains normally will last the life of the engine and are replaced during an engine rebuild.
chain
Yes , it must have a timing CHAIN ( the Gates website does not list a timing belt for the 2004 Nissan Xterra 2.4 liter )
It should not need to be replaced under normal conditions.
No, under normal circumstances the timing chain will last the life of the engine and is replaced when the engine is overhauled.
A bent valve(s).
chain