KATHOPNISHADA CHAPTER 1 SHLOKA 16

     
                                           तमब्रवीत् प्रीयमाणोमहात्मा

                                          वरं तवेहाद्य ददामि भूयः

                                           तवैव नाम्ना भविताऽयमग्निः

                                          सृङ्कां चेमामनेकरूपां गृहाण ॥ १६


                                  TAM ABRAVIT PRIYAMAN MAHATMA

                               VARAM TAV IHA ADYA DADAMI BHUYAH

                              TAV EVA NAMNA BHAVITA AYAM AGNIH

                           SRUKAM CH IMAM ANEK RUPAM GRUHAN ||16

            SATISFIED (LOVING) YAMA(DEATH) SPOKE TO HIM I GIVE YOU THE

             OTHER BOON,THE FIRE SACRIFICE WILL BE NAMED AFTER YOU,

                                AND TAKE MANY COLORED CHAIN ||16

     The Lord of Death or YAMA is granting the second boon and telling Nachiketa that the Universal Fire sacrifice will be named after You  and then offered him a chain of many colors.The first part is easy to understand. The Fire sacrifice is done for many years  and centuries . We have heard stories in Ramayana, that the sages were doing the Fife sacrifice and the Demons were coming to destroy it. Then Rama came in and protected the Sacrificial ceremonies. I have often wondered as to is this really physical Fire sacrifice called YADNYA and there were real Demons that came physically to destroy it and Rama came physically to help or was it that the sages were doing mental meditation , GIVING UP everything  and demonic thoughts - The Demons came  and disturbed the meditation and then when they prayed or concentrated on RAMA the supreme being, the demonic thoughts went away and the mental sacrifice of giving up every thing and achieving the meditation was complete peacefully. 
    In any case it could be the ritual that was explained or the technique of meditation was explained  and he was told that that will be named after him - just like a surgeon develops a surgical technique and it is named after the surgeon.
    But the next part is not easy to explain.. Why would the YAMA give him a chain or garland of many colors? In overall skim of teaching Nachiketa the meditation this does not make any sense. Could it be some special thing by which he could do the meditation quickly or was it it something like mortals giving gifts or may be it was just a gift and nothing more . In any case I do not have any special explanation for it .