Override GenerateNuspec or other targets in Directory.Build.targets

I expected that Directory.Build.targets is imported at the end of the Microsoft.NET.Sdk. Unfortunately some targets seem to be defined before the directory.build.targets has been imported, which prevents me from overriding them. Is there a property (which i could set in directory.build.props) to a target file that is imported after everything else is already specified? Is there any other possibility to override targets like GenerateNuspec without changing the standard project file format (with Sdk attribute in the project tag)?