The chain cranks get worn quickly. So, when the front shifting becomes less than optimal after replacing the chain, then check the teeth on the rings. If the ring turns out to be hook and thin, then it’s time to replace it. However, some cranks can only use exclusive rings, whereas some run on universal components. Thus, try to match the combination of the rings accordingly. However, get the proper bolt-circle diameter for your crank. Therefore, while replacing the rings, try to remove the crank to make the job easy. You can inspect, service or maybe replace the bottom bracket.