The Nintendo Switch has a 6.2-inch, 720p LED display. According to this Bloomberg article, it's possible we'll soon be seeing a new premium Switch model with a 7-inch, 720p OLED display.
From the Bloomberg piece:
Samsung Display Co. will start mass production of 7-inch, 720p-resolution OLED panels as early as June with an initial monthly target of just under a million units, said the people, who asked not to be identified discussing internal matters. The displays are slated for shipment to assemblers around July, the people said. Representatives for Nintendo and Samsung Display declined to comment.
"The OLED panel will consume less battery, offer higher contrast and possibly faster response time when compared to the Switch's current liquid-crystal display," said Yoshio Tamura, co-founder of display consultancy DSCC.