yeah its 15 years old dude
they get tired and old
probably 100+ on the clock ?
i think a recondition and rebuild is maybe $500
for stocker parts - nissan service interval i think is 100,000 for the stock run of the mill ball bearing turbo chargers so yours is probably past that
mines on 165,000 (r33 though) and still going, just luck of the draw and usage patterns i guess