Hello Q, and welcome to the Forum.
First off, it's always best to replace the chain and sprockets together. Worn sprockets can seriously reduce the lifespan of a new chain.
I don't know the spec of the NSR150SP chain, but I doubt it's anything out of the ordinary. Do you know the chain size? You should be able to buy a pattern chain from most manufacturers... anything from a £10 budget non-O-ring to a £50 gold X-ring, and anything in between. It will just need shortening to the required number of links, which any bike shop should be able to do for you if you don't have a chain splitter.
For example, I use an £18 non-O-ring 520 chain on my MC21. I buy one 112 links long, and then shorten it to the required size (currently 107 links I think) to work with whatever gearing I choose to run. I tend to replace my chain twice a year, or swap chains when I change gearing, so they don't get too much use, but some choose to run £50~60 chains as they may be fitted for a year or more -- each to their own.
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Andy.
NSR-WORLD.COM
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