Resolution will be based on Nintendo Investor Relations data.
As of the March 31st, 2023 update to their numbers, the Switch has sold 125.62 million units so far.
The current best-selling videogame console of all time at the time of market creation is the Playstation 2. The last official sales number from Sony with regards to the Platstation 2 is 155 million units, so this will be the number to beat, unless Sony updates this to a higher number at some point. (https://sonyinteractive.com/en/our-company/business-data-sales/)
If Nintendo report that the Switch has sold more than 155 million units at any point before 2026, this market will resolve YES. If they don't, NO.