Currently there are no official plugins for Nebula or Disney+ available. However there are video plugins for those and multiple other services available in the amazing repository of Matt Huisman, alias Slyguy.
To install any of the provided addons, you need to add the slyguy repository zip file from either directly from k.slyguy.xyz or use the mirrored zip file below:
Now you can install one of the many plugins from this repo.
If you like this work, then please also consider buying Matt a coffee.