This is fairly common knowledge, but if I can save some people from an unwanted auto renewal, then it's worth the post.
If you only plan to use BTN+ for these remaining two Nebraska basketball games this nonconference season, you can go to your account right now (like, right now) and click "discontinue subscription" (or whatever the verbiage is) and you will continue to have access to watch games through the remainder of the month you signed up for. No auto renewal headaches.
Personally, I signed up and within 10 minutes I clicked that "cancel" button and have been able to watch the two games just fine.