To allow selection of the package management format for new projects, click on Tools in the menu strip and choose Options. In the options window, navigate to the NuGet Package Manager section in the tree on the left.
As you can see, you can not only select the default package management format, but you can also opt to get a choice of format selection every time you install the first package into a project. When you do this, the next time you install a NuGet package in a new project, you will be presented with the following dialog:
We have been on quite a roller-coaster with constant changes of NuGet package management formats, but it seems we finally have a definite winner that should be here for the years to come. Visual Studio however doesn’t yet force nor recommend you to use this format, but luckily you can choose to do it manually with a little more work.