Where did Jesus say he had seen Nathanael before Philip called him?

Answer: Under the fig tree

Jesus said, "Before Philip called you, I saw you under the fig tree." Nathanael declared, "You are the Son of God!"

“When Jesus saw Nathanael approaching, He said of him, “Here is a true Israelite, in whom there is no deceit.” “How do You know me?” Nathanael asked. Jesus replied, “Before Philip called you, I saw you under the fig tree.” “Rabbi,” Nathanael answered, “You are the Son of God! You are the King of Israel!””— John 1:47-49 (BSB)