Directly, I don't think so. Youtube letting anyone join in, and generally being free to use, are the opposite of what Nebula does. Closest to Youtube afaik are Peertube, Odysee, Rumble and Bitchute. Other platforms come to mind but imo it starts getting a bit too small/niche at this point.

Nebula, and Dropout if I may add, from what I understand and checked, would be closer to cable TV, or Netflix and the sort if they were more generalist (or let their creators be). Still, subscribing to both, I think the two are worth to have around.

Now, on tangent, but still in the scope of escaping Youtube, from my experience, it is something hard to achieve. Constantly seeking redundancy for what I follow, still about half the video channels are Youtube-only, and jumping across sites only helps to annoy and want to stay at a single place (imo the intended experience from what I call the "2010's sites").

To avoid this annoyance, if you can, I'd suggest trying to aggregate all alternatives in a single place, like RSS readers, Grayjay/NewPipe/PipePipe, here at the fediverse through tracking bots, Peertube channels being treated as communities, etc., and/or other aggregators you may find. Helps at easing the process and not be annoyed into ~~submission~~ sticking to the more overarching platform.