Here is a rather standard Greek icon of St. Nicholas:
He is shown an a very hieratic posture, dressed in his bishop’s garments, and seated on a cushion with his feet on another cushion.
His chair is technically a bishop’s kathedra (καθέδρα) — commonly known as a bishop’s throne — a symbol of his office. Our word cathedral comes from it — originally the church in which the main seat of the bishop was found.
He holds the open Gospels in his left hand, and if we look closely we can see the text:
Though it is a bit dark, we can nonetheless see it well enough to know that it is written not in the majuscule (capital) letters of older Greek icons, but largely in a more cursive minuscule (lower case) text. And we can see that it begins
Εἶπεν ὁ Κύριος …
Eipen ho Kyrios …
“The Lord Said …”
Kyrios is abbreviated, as it often is in Greek icon inscriptions.
That is a beginning often used in Russian icons for quotes from Jesus, though of course written in Church Slavic rather than Greek.
Then comes the quote, which as we can see from what is legible, repeats the beginning part of this portion of John 10:9:
Εγώ εἰμι ἡ θύρα· δι’ ἐμοῦ ἐάν τις εἰσέλθῃ σωθήσεται καὶ εἰσελεύσεται καὶ ἐξελεύσεται καὶ νομὴν εὑρήσει.
Ego eimi he thura di emou ean tis eiselthe sothesetai kai eiseleusetai kai exeleusetai ka nomen euresei.
“I am the door: by me if any man enter in, he shall be saved, and shall go in and out, and find pasture.”
We don’t really need the title inscription to identify this image as Nicholas, but here it is nonetheless.
It is the standard HO HAGIOS — “The Holy” — but written here with ligatures. And on the other side is the personal name:
Nikolaos — the Greek form of Nicholas.
So together it reads
HO HAGIOS NIKOLAOS
“(The) Holy Nicholas.”
Or as we would say in English, “Saint Nicholas.”
Nicholas was an immensely popular saint in Greece, as he was in Russia.