Route 1: You want the potential to make the biggest profits; you have time and money to invest; you are willing to risk heartache, despair, family breakdown and sleepless nights.
This is the one I wouldn't contemplate, and it involves going the 'whole hog': researching the market, analysing your competitors, registering a domain, building your own sleek online store (not as difficult as it sounds with the great templates and simple front end of a product like shopify becoming available), negotiating with wholesalers, holding stock, managing delivery, dealing with customers, promoting the business, etc., etc.
If this you, give me shout under my 21 Thoughts guise, and if I can't persuade you not to, I'll do my best to help you.
Route 2: The 5-minute route
Thanks to an offering called Zlio you can now build your own online shopfront without any of the hassles of actually having a shop. Register, choose the products you want to offer from a range of other vendors, e.g. Amazon and buy.com, and let them deal with all the rest. You get a commission on each sale that you share with Zlio.
The downsides: it's only available in France and the US at the moment (UK coming soon), chess supplies from the available vendors are limited, and you still have to promote it and get visitors to your store.
If you are serious, my advice is make it niche and promote, promote, promote. Let me know how you get on.
Route 2.5: Don't!
If you already have a blog or website, take the simple route and host adverts (be an affiliate) for an existing chess store, e.g. the London Chess Centre, that pays commissions on customers you send to their shop.
Good luck and happy monetizing!