In that case, of which I take your words for it and didn't bother to check any of his video and believe that information of his access point and his marketing contract with chips.gg are verifiable, then yes, not only it's a violation of ToS, chips.gg can also be considered to provide a questionable marketing strategy as it poses a risk to cast an impression that US resident can play on their platform.

Granted, it's each and every users' responsibility to read the ToS and understand the territory being restricted by each and every platform, but I'll have to say that the marketing ploy made by the streamer will raise an ambiguity and confusion on whoever followed his channel.