Hi Fabio,
You can workaround this in two ways:
1. Tell the Y axis to always place the labels inside its ruler range - this is achieved by the following code:
NLinearScaleConfigurator scaleY = (NLinearScaleConfigurator)chart.Axis(StandardAxis.PrimaryY).ScaleConfigurator;    
scaleY.LabelStyle.KeepInsideRuler = true;
2. Specify some top margin:
chart.Margins = new NMarginsL(0, 7, 0, 0);

Hope this helps - let us know if you meet any problems or have any questions.

Best Regards,
Nevron Support Team

I wanted to have the chart fill up the whole NChartControl so I have set its properties like this:

Chart.Bounds = Bounds.Stretch
Chart.DockMode = PanelDockMode.Fill

That works nicely but some of the ticks' label are not showed completely. I was wondering if there is a property or a way that adjusts the tick's label so that is ends up inside the NChartControl. 

As you can see in the picture below the tick label isn't showed completely.