Keep forgetting these lines, so sticking them here for future reference.
Spec
nuget spec SomeProject.csproj
Fix up created nuspec file afterwards.
Pack and Publish
nuget pack SomeProject.csproj -Build -Symbols -Properties Configuration=Release
nuget push [main nupkg file created by previous command]
nuget push [main nupkg file created by previous command]
This will pack and push to both the public NuGet feed and to SymbolSource.