You can't specify a search folder as such.
To explain, the UGII_TEMPLATES_DIR is not for the template files (ie. NX part files), but the PAX files that define the options available in File -> New.
By defining that variable, you're telling NX to only load the PAX files that live in the folder defined by that variable.
The location for the actual part files/templates are then specified in the PAX file. In the example below cut from a model PAX file, the section in bold specifies the part to load & use as a template.
<PaletteEntry id="d1">
<References/>
<Presentation name="Model" description="NX Example with datum CSYS">
<PreviewImage type="UGPart" location="model_template.jpg"/>
</Presentation>
<ObjectData class="ModelTemplate">
<Filename>model-plain-1-inch-template.prt</Filename>
<Units>English</Units>
</ObjectData>
</PaletteEntry>
If you want to use subfolders, you could specify the full path to the file instead:
<Filename>c:\NXtemplates\model-plain-1-inch-template.prt</Filename>
It might be possible to use variables in the PAX, but I've never tested that.
Anthony Galante
Senior Support Engineer

NX4 to NX CR with almost every MR (18versions)