I am supported by God's word in denying that Nero "was, is not and yet is", since Nero is not immortal. Nero and the other Roman Emperors can all be labeled an "antichrist" but none of them are the beast of Revelaton.
1 John 2:18-19
18 Children, it is the last hour; and just as you heard that antichrist is coming, even now many antichrists have arisen; from this we know that it is the last hour. 19 They went out from us, but they were not really of us; for if they had been of us, they would have remained with us; but they went out, in order that it might be shown that they all are not of us.
NAS
1 John 2:22-23
22 Who is the liar but the one who denies that Jesus is the Christ? This is the antichrist, the one who denies the Father and the Son. 23 Whoever denies the Son does not have the Father; the one who confesses the Son has the Father also. NAS
1 John 4:1-3
4:1 Beloved, do not believe every spirit, but test the spirits to see whether they are from God; because many false prophets have gone out into the world. 2 By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God; 3 and every spirit that does not confess Jesus is not from God; and this is the spirit of the antichrist, of which you have heard that it is coming, and now it is already in the world. NAS
Also the peace sign, which has come to be known as Nero's Cross did not even exist before 1958.
Peace Symbol History with Q&A
The Broken Cross