Nebuchadnezzar was stating what he observed when he said "and the form of the fourth is like the Son of God [or 'a son of the gods']." What he saw, he could only describe as something that looked god-like. Now, I would say that for Melchizedek to be "made like unto the Son of God" is quite different from Nebuchadnezzar trying to describe someone he saw as "the form... is like the Son of God."
Taking note of the following verses, let me ask a question.
Verses. Acts 13:33 God hath fulfilled the same unto us their children, in that
he hath raised up Jesus again; as it is also written in the second psalm, Thou art my Son,
this day have I begotten thee.
Hebrews 5:4-10 And no man taketh this honour unto himself, but he that is called of God, as Aaron. So also Christ
glorified not himself to be made an high priest;
but he that said unto him, Thou art my Son, to day have I begotten thee. As he saith also in another, Thou a priest for ever after the order of Melchisedec.
Who in the days of his flesh, when he had offered up prayers and supplications with strong crying and tears unto him that was able to save him from death, and was heard in that he feared; Though he were a Son, yet learned he obedience by the things which he suffered;
And being made perfect, he became the author of eternal salvation unto all them that obey him; Called of God an high priest after the order of Melchisedec.
Questions.
Was the resurrection of Jesus the Christ by God the Father an absolute necessity to Jesus being a priest forever after the order of Melchisedec?
Concerning, And being perfected/matured/completed he
became; How was he perfected/matured/completed?
Concerning, Who in days of the flesh of him; Would 1 Cor. 15:46 be relative to, Who in the days of the flesh of him? 1C15:46 Howbeit that not first which is spiritual, but that which is natural; and afterward that which is spiritual.
Assuming afterward meaning after the resurrection and Jesus being the only one to this date so resurrected.
BTW I believe Mel to have been a man and is presently dead awaiting the resurrection in which he will still be a priest.
I believe this thought carries on through chapters 6 and 7 where in 6:20 this is said; Whither
the forerunner is for us entered, [even] Jesus, made an high priest for ever after the order of Melchisedec.
If we also are to be priest in the kingdom of God, after what
order shall we be priest?