Probably not. It's designed to keep some traffic through your internet from interfering with higher priority traffic through your internet. If the higher priority traffic is laggy to begin with it will still be laggy, even with this product. It just won't get as much interference from other programs on your PC that might also be transferring data.
If you are normally transferring data while playing on chess.com it might be able to help. They don't say how they determine between different types of traffic. Depending on how they do that determines how powerful and/or flexible that product is. If it can be set to recognize chess.com game traffic then it should be able to keep other downloads, Skype, streaming radio, etc. from causing more lag. It won't be able to fix lag that is not created from within your PC.
Does this reduce lag on chess.com: http://www.team-dignitas.org/articles/scene/Bigfoot-Networks/100/Advanced-Stream-Detect-on-Killer-Networking-Platforms/
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