Yes, to stream the espn channels it is necessary to use a streaming service like Sling which is what I use. To get espn+ you must download the ESPN app onto a streaming device like a roku or a smart phone. Since I live in Colorado I have no choice but to stream ESPN+ or the midcosportsplus app to watch UND sports.
The easiest way to stream espn3 is with a Sling TV Orange subscription. With other streaming services like hulu and youtube tv, you must go through the rigamarole of enabling the espn app to pull espn3 from the streaming service and imbedding it within espn+ . The best way I found of accomplishing this rather convoluted task is to follow the directions given in a website called "grounded reason".
I'm sure that's all clear as mud, and I'm still not as certain as I'd like to be as to what the viewing options for the UNI game are.