I have a shapefile polyline which I would like to add nodes to at set intervals along its length.
Is this possible in ArcGIS 10.2 and how would I go about it?
There are many tools on the ArcScripts website that can do this sort of thing. Search for this tool Create Points on Polylines or if you want to insert them into the underlying polyline geometry have a look at Densify_June_2013.
I think you might be looking for the densify tool... Select your line segment and run the densify tool to add vertices along the line.
Or you could use the split tool to break it into individual segments. split
Have a look at this tool by Ian Broad @ian. It seems like it would do exactly what you need.
Create Points on Polylines
Additionally, the arcpy.Polyline().positionAlongLine() method will also generate a point which you can write to a Point feature class, if you are okay with Python scripting.