Okay, what in the world is going on here? A few days back, we noticed that Nintendo's Switch Online website had a blurb at the bottom that mentioned what their Switch NES controllers could be used for. As a matter of fact, the blurb is still up. Here's what it says.
Please note: Nintendo Entertainment System Controllers can only be used while detached from the Nintendo Switch system, and only to play NES – Nintendo Switch Online games. Nintendo Entertainment System Controllers can be charged by attaching to the Nintendo Switch system.
Here's where things get screwy. If you go over to the Switch NES controller FAQ/Overview, you'll find this blurb.
The NES controller is designed for use with NES - Nintendo Switch Online games and is not guaranteed to work with other software.
The wording in that response certainly makes it seem like other titles might be able to support the controller. If I read that first, I would have ordered the damn things!
Thanks to JJTheTexan for the heads up!