I use amazon usa website and select the filter as 'eligible for international shipping'. I have sent car parts, they come by DHL is 3 to 5 days and are not expensive. however a gaming chair is quite big so might be more I guess.

alternative is google 'shop and ship' and 'drop and ship' there are a few companies who can send it where you order your delivery to a usa address then they forward to you. I have not tried them though.