Lord Siva addressed his wife, Durga: "O Varanana (lovely-faced woman), I chant the holy name of Rama, Rama, Rama and thus constantly enjoy this beautiful sound. This holy name of Ramacandra is equal to one thousand holy names of Lord Vishnu (Vishnu-sahasra-nama-stotram)."
(II) In the Padma Purana it its mentioned:
visnor ekaika namapi, sarva vedadhikam matam tadrk nama sahasrena, rama nama samasmrtam
"Each Name of Lord Vishnu is greater and more potent than the entire Vedas combined together, and Lord Rama's Name alone is more superior that a thousand Names of Lord Vishnu."
(III) In the Brahmanda Purana it is stated:
sahasra-namnam punyanam, trir-avrttya tu yat phalam; ekavrttya tu krishnasya, namaikam tat prayacchati.
"And the pious results (punya) achieved by chanting the thousand holy names of Vishnu (Vishnu-sahasra-nama-stotram) three times or the Holy Name of Rama thrice can be attained by only one utterance of the Holy Name of Krishna."
"O Arjuna, the Holy of Krishna is the most principal (mukhyataram) among all Names of God. One can atone for unlimited sinful deeds by chanting the Name of Krishna which is the supreme destroyer of all sins."
"The Holy Name Krishna Chaitanya or Gauranga is the topmost or the most principal (mukhyan) even among all the important primary and most principal (mukhyatamam) Holy Names of the Lord Krishna. By chanting this name just once, a person attains the spiritual results (punya) of chanting all the other holy names of the Lord."
So from the above five very important verses we can easily come to the following conclusion:
Secondary Names of God like Brahma, Paramatma, Shrishtikarta etc. take us only to the heavenly planets or maximum can grant us liberation or mukti. But the following Primary Names of God can elevate the soul to the Vaikuntha planets in the spiritual world:
Vishnu's Name = Principal Name of God more than all the Vedas combined together
Rama's Name = More Principal Name (Mukhya) of God =1000 Names of Vishnu
Krishna's Name = Most Principal Name (Mukhyataram) of God = 3 Names of Rama or 3000 Names of Vishnu
Gauranga's Name = Most Principal (Mukhyan) among the Most Principal Names (Mukhyatamam) of Krishna = Sum Total of all the result achieved by chanting the Names of Krishna, Rama and Vishnu
Please note there is absolutely no difference between the Holy Name of Krishna and Gauranga (They are of equal potency totally non-different) for the liberated souls but for the conditioned souls the Name of Gauranga is even more beneficial than the Name of Krishna. Thus the above difference as described in the scriptures is purely due to the difference in benefit achieved by the chanting of These Names by the conditioned souls not the liberated souls. Since there is no difference between Krishna and Gauranga, the liberated offenseless souls get equal benefit form chanting the Nityananda and Gauranga Mantrarajas and the Hare Krishna Mahamantra so for them they can chant anyone and get the same absolute benefit. But that is not applicable to the conditioned souls because their ten offenses block the full light and power of the Hare Krishna Mahamantra from coming through in the conditioned stage. But as per Navadvipa Dhama Mahatmya (aparadha sattva jiva labhe prema dhana and aparadha badha tara kichu nahi kare) the experience the full potency and power of the Nityananda and Gauranga Mantrarajas is fully available even to the conditioned and offensive chanters.
Mukhya is the first degree, Mukhyataram is the second degree and Mukhyatamam is the third degree of emphasis. So in the above verses from the scriptures, Rama's Name is Mukhya, Krishna's Name is Mukhyataram and Gauranga's Name is Mukhyan Mukhyatamam.
In the Vishnu-yamala it is said:
krishna-chaitanya-namna ye, kirtayanti sakrn narah; nanaparadha-muktas te, punanti sakalam jagat.
"Those who chant the name of Krishna Chaitanya or Gauranga even once, become free from all offenses and purify all the worlds by their very presence."
Shrila Jagadananda Pandita says in Prema-vivarta:
gaura ye visala nama sei nama gau; anya saba nama-mahatmya sei name pau.
"The most powerful names of God are the names of the most merciful incarnation of God, who is known as Lord Gauranga. The glories and power of all the other names of God are completely present in the Names of Lord Shri Gauranga Mahaprabhu and thus They should be constantly chanted."
So considering these authorized scriptural statements about the supreme glories of Lord Gauranga's Name which person in this world will not chant the Nityananda and Gauranga Mantrarajas along with the Hare Krishna Mahamantra? And who can have the courage to challenge all the above Vedic statements and stop others from chanting the most merciful Names of Nityananda and Gauranga along with the Mahamantra.