if you need fine-grained control over the layout and content of your NuGet package, then you should create a nuspec
file and use that to create the package. Then you can add files with the following syntax, for example:
<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
<metadata schemaVersion="2">
...
</metadata>
<files>
<file src="Foo.dll" target="lib\net45" />
...
</files>
</package>