https://www.gamespot.com/articles/snes-classic-returns-at-walmart-again-today/1100-6454950/

Having trouble finding a SNES Classic? Retailer Walmart has announced that the mini console will be in stock this week, November 15-17. Units will be available starting at 11 AM PT / 2 PM ET each day, which means you have a total of three chances to purchase one. [Update: It's now Thursday, and you'll have another opportunity to grab a SNES Classic at the aforementioned today today. Yesterday's allotment went extremely quickly, so you'll need to act fast if you're interested.]

There is a limit of one per customer, and Walmart says supply is going to be "limited." It appears the units will be available on Walmart's website, though it remains to be seen if there will be units available in-store as well.