Add missing `err != nil` check

controller/nucleus/principalNetworkDomain.go

@@ -149,6 +149,9 @@ func (pnd *pndImplementation) Commit(u uuid.UUID) error {
 
 	// Set all the changes within the network elements model
 	networkElement, err := pnd.networkElementService.Get(store.Query{ID: ch.AssociatedDeviceID()})
+	if err != nil {
+		return err
+	}
 	diff, err := ygot.Diff(ch.PreviousState(), ch.IntendedState())
 	for _, update := range diff.GetUpdate() {
 		opts := []ytypes.SetNodeOpt{&ytypes.InitMissingElements{}, &ytypes.TolerateJSONInconsistencies{}}