The problem with this is that I don't think bankruptcy courts/proceedings work that way. The TV rights are assets that all the creditors will have claims on, not just the NHL. They will have to be dispersed in a chapter 7 liquidation filing in a way that makes as many creditors whole, so no "buying back on the cheap" is going to happen. That would mean that between the filing and the dispersal of the assets, the credit holders (NHL and teams) would get no money from the assets/rights. What could be even worse is a chapter 11, where they are trying to reorganize and some of the creditors will need to take a markdown on what they are owed. I don't know if license fees would apply here, but if they do that could mean the Balley's still gets to broadcast the games, but gets to pay the NHL and teams less than what was agreed to.
All that said, I doubt the leagues are "hoping" they go tits up.