Nuke uses the iNodes OFX plugin. The plugin brings the nodes, and the Nuke card adds the link that brings your results back into it.
Find the nodes
Look for iNodes in the list of OFX nodes. They're sorted by category, then by model family.
The fastest way: in the Node Graph, press Tab and type a few letters of the model, “ltx alph” for example. Your Comfy nodes are there too.
Where your results land
The result comes back as a Read node, placed under the iNodes node, image sequences included. Wire it into the Viewer, or compare it with your shot using the Viewer's wipe.
Everything else
The buttons are the same everywhere: see Anatomy of a node.