One of the few things that are practically mandatory for developing in Angular is an extension similar to the Angular Language Service. Speaking as an Angular developer, this is the main reason why I don’t use Nova as an IDE in my daily work. This is sad as I feel it is the most complete and well made IDE for macOS.
I don’t believe there are any limitations in the Nova extension API that would prevent someone from being able to make an Angular language server plugin. If you know of any such limitation specifically let us know.