Non-profits sell swag all the time, our little AMA.ORG here is a perfect example,, they sell all kinds a stuff

Selling as a non profit is perfectly legal,, what matters is what you do with the proceeds or profits,, if they go back into the cost of operating the Org. it's perfectly legal

I hate to break it to you,, the LHS is a thing of the past,, just a few dinosaurs hanging on