Hello Christiano,
Nevron Gauge is not available as a separate Toolbox item in VS. It is part of the Nevron Chart component (NChartControl) and it is included with the Enterprise edition.
For assistance with creating a simple gauge, please take a look at the following post: http://forum.nevron.com/shwmessage.aspx?forumid=1&messageid=3592
You should also review the online help documentation: http://helpdotnetvision.nevron.com/
Chart for .NET >> User’s Guide >> Gauges >> Overview