Open Layer Properties from the GIS Tools tab
In the Layer Properties window, click Junction under the Node group in the layer table and select the Label tab
Check on Display Label. In the drop-down list of Attribute, select NHYD. Then, click Apply.
Keep the Layer Properties window open. Following the same way as junction label, add NHYD label to Subcatchment, Conduit and Outfall. Close the Layer Properties window once finished. The map will display like this: