Assuming that you'll have to subscribe for their service to view on BTN+. If I had to guess I'd say this is a similar model to ESPN+ where a cable subscription doesn't grant you access.
Have any of OUr games been broadcasted on ESPN+ this year?
Some of the away games have been. The home games are simply on YouTube. Not high quality but free for everyone.
Big Ten plus costs $9.95/month, though I think free trials are available through other streaming services.