TOKYO—Nintendo Co. kept its sales forecast for the Switch console unchanged despite strong demand, reflecting what analysts said is a supply bottleneck that could hurt the company during the critical year-end holiday season.

Kyoto-based Nintendo said Wednesday it sold 1.97 million units of the handheld-console hybrid game machine in the April-June quarter and is sticking to its forecast of 10 million for the current fiscal year, which ends next March.

...