Depends on the translation, obviously since the greek doesn't have capital letters.

Textus Receptus:

απεκριθησαν αυτω ιησουν τον ναζωραιον λεγει αυτοις ο ιησους εγω ειμι ειστηκει δε και ιουδας ο παραδιδους αυτον μετ αυτων

KJV italicises it

‭John 18:5 KJV‬

They answered him, Jesus of Nazareth. Jesus saith unto them, I am he. And Judas also, which betrayed him, stood with them.

NASB capitalises it

They answered Him, “Jesus the Nazarene.” He *said to them, “I am He.” And Judas also, who was betraying Him, was standing with them.

NIV, ESV and USNT don't

“Jesus of Nazareth,” they replied. “I am he,” Jesus said. (And Judas the traitor was standing there with them.)

They answered him, “Jesus of Nazareth.” Jesus said to them, “I am he.” Judas, who betrayed him, was standing with them.

‭“Jesus o Nazareth,” the' reponed. “A be hïm,” qo he. (An Judas tha bethrayer wus stud thonner alang wi thaim.)