It's about completely the same thing what she's singing in "That Made Me Stronger" - Petty telling her not to ask him to write her a song but to believe in herself again and start writing by herself. And if you read Nicks's comments or interviews you can know that to addition to that she's recalling also that he told her to forget about her past (Street Angel, Konopin etc.) and begin everything from the start. As she says - you have to let Tom go, which means you have to let him speak because he always gives good but hard advice.
It's about completely the same thing what she's singing in "That Made Me Stronger" - Petty telling her not to ask him to write her a song but to believe in herself again and start writing by herself. And if you read Nicks's comments or interviews you can know that to addition to that she's recalling also that he told her to forget about her past (Street Angel, Konopin etc.) and begin everything from the start. As she says - you have to let Tom go, which means you have to let him speak because he always gives good but hard advice.