I don't know how the credit thing works on the NBC app, but you can watch them on the Peacock channel/app.
https://channelstore.roku.com/details/2dd1a2670117700b87d7a40bfa7e6138/peacock-tv
I would recommend setting up an account on their website (https://www.peacocktv.com/plans/all-monthly ) and then signing in on your Roku after launching the above channel/app. They have a free signup (https://www.peacocktv.com/freesignup ), but I don't know what that gets you.
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