KATHOPNISHADA CHAPTER 1 SHLOKA 19

                                                   एष तेऽग्निर्नचिकेतः स्वर्ग्यो
                               
                                                    यमवृणीथा द्वितीयेन वरेण ।
               
                                                एतमग्निं तवैव प्रवक्ष्यन्ति जनासः

                                                  तृतीयं वरं नचिकेतोवृणीष्व ॥ १९

                              ESH TER AGNI NACHIKETAH SWAARGYO

                                    YAM AVRUNITHA DWITIYEN VAREN |

                        ETAM AGNI TAV EVA PRAVAKSHYANTI  JANASAH

                          TRUTIYAM VARAM NACHIKETO VRUNISHVA || 19

OH NACHIKETA,THIS THE FIRE WHICH LEADS TO HEAVEN AND WHICH YOU

   CRAVED FOR BY SECOND BOON. THIS WILL BE CALLED BY YOUR NAME .

                                ASK FOR THIRD BOON OH NACHIKETA ||19

      This is continuation of the last Shloka  and so the lord of DEATH is telling that the Fire ceremony will be called Nachiketa Fire . This is the Yadnya or sacrificial ceremony, that will lead to HEAVEN for the host or the Yajaman. He tells that he has educated the knowledge of such action that leads to heaven . This is such an important ritual that it will be called by Nachiketa's name.

    This can be compared to the Satyanarayan Katha or the Pooja that many Indians do to end the sorrow in this Mortal world  and get Heavenly pleasures. So this is continuation of the same theme.
He is now asking Nachiketa to ask for the last and the third boon.