Hi @grinn2!
You were very close. This is the node you’re looking for:
Welcome to editor scripting! You’ll have many similar headaches ahead of you haha. As someone who has been making editor tools for quite a while, the best piece of advice I can offer is to work backwards. There is a lot of overlap between gameplay nodes and editor nodes (as you’ve discovered) and it is rarely obvious which ones you can use for scripting. In this case, you knew you wanted to open a level, so start with a level editor subsystem node, since their functionality is limited to in-engine tooling for the most part. Dragging out from that pin will give you a list of context-specific nodes, so you can safely assume that most of those nodes can be used with the editor. In your case, dragging out from the Level Editor Subsystem and typing in “Level” gives you these options:
Best of luck with your scripting!