Generate API ref docs from NuGet packages

I'd like to be able to use docfx to generate API ref docs from my already built NuGet packages. The packages already contain the built .NET assemblies and the XML doc files. Ideally, I'd like to be able to create my package list (maybe as PackageReferences in a .csproj file?) and then point docfx at the list. Docfx would then restore the packages and handle the API ref doc generation.