The priests may have sent Nicodemus
to find out more from Jesus because
they were not satisfied with the answer
He gave them.

Whether He went for them or on his
own, we know he went secretly not
wanting anyone to know of his visit.

Nicodemus saw Jesus as a prophet and
said that He must be of God. But had
not accepted Him as Messiah.

John 3;2 in verses 3 & 4 Jesus tried
to explain to him of the kingdom of
God.

Nicodemus was puzzled by this and
said very little. Jesus continued on
explaining spiritual things. He left
Jesus bewildered, each time he is
seen in public he defended Jesus.