yes muk33, for several reasons, 1, you are over the recommended miles, 2, belts are rubber, therefor subject to dry rot so should be changed at either 105k OR every so many years ( I cant recall right now if its 5 or 7 years) either way you are there.

Also, There is more to change at the same time as the timing belt, other than the belt. Such as the Tensioner, the water pump, etc.. look up the belt kit for your X on Courtesynissan.com and you will see what all is included, that they recommend you should change out when doing the belt.

even if you've never had one break, dont forget that after that much use and abuse, the belts can also stretch, tensioners can lose tension, and the belt could skip, or jump a tooth somewhere, that could cause major damage to the engine.