These titles will be available for download beginning on May 15. With the new additions, the catalog of NES freebies climbs to 40. The library launched last year with 20, with more titles being added on a monthly basis to expand the appeal of the service. For reference, April’s additions included Punch-Out!!, Super Mario Bros. The Lost Levels, and Star Soldier.
— Nintendo of America (@NintendoAmerica) May 8, 2019
Access to a library of free NES games is one the perks of signing up to Nintendo Switch Online. Other benefits of Nintendo Switch Online is access to cloud saves (for some games) and of course the ability to play titles online to begin with.
A subscription to Nintendo Switch Online costs $4 USD/month or $8 USD for three months. A 12-month membership is available for $20 USD, while a Family Membership for up to eight Nintendo Account members costs $35 USD for a year. New subscribers can sign up with a seven-day free trial.
from GameSpot – Game News https://www.gamespot.com/articles/free-nes-titles-for-switch-online-subscribers-reve/1100-6466725/