In John 1:49 Nathaniel refers to Jesus as "the Son of God" and "the King of Israel." -- There is no record of Jesus rebuking him in any manner, no correction.
Matt. 2:2 - The wise men asked "where is he that is born King of the Jews?" This was when he was a newborn.
In Matt. 2:11 we see the gifts brought to Jesus as a newborn babe, i.e., gold, frankincense and myrrh. These are gifts given to a King.
Luke 19:12, 15 - Jesus describes himself as the young nobleman who goes to a far country (heaven) to receive a kingdom. Then, in vs. 15, he returns "having received the kingdom."