CoreProj1 references CoreProj2 and CoreProj3
  CoreProj2 and CoreProj3 do not reference anything

dotnet pack "full project path" --output "outputPath"

Error NU1101  Unable to find package CoreProj2. No packages exist with this id in source(s): LocalPackages, Microsoft Visual Studio Offline Packages, nuget.org,  TestNuget   sourcereposTestNugetTestNugetTestNuget.csproj   1