Tsar Slavy - King of Glory
IC XC - Jesus Christ
Syn Bozhiy - Son of God
NIKA - Victor, Conqueror
Don't forget that the skull is also used as part of the phrase: The King of Glory, Jesus Christ the Son of God, conquers death.
I have never thought that the various words and abbreviations formed a sentence. I have always thought they were discrete entities. But I am sure your interpretation is possible too.
By the way, if we look at the skull it has a letter on either side Г and А =
Голова
Адама which means The Head of Adam.