Musically, Chelsea Girl is best described as a cross between chamber folk and 1960s pop. The musical backing is relatively simple, consisting of one or two guitars or, alternatively, a keyboard instrument, played by either Browne or (a combination of) her Velvet Underground colleagues. There are no drums or bass instruments. Adding to the chamber folk feel of the music is the strings and flute arrangement superimposed over the initial recordings by producer Tom Wilson and arranger Larry Fallon without involving or consulting Nico.
Nico was dissatisfied with the finished product. Looking back in 1981, she stated:
“I still cannot listen to it, because everything I wanted for that record, they took it away. I asked for drums, they said no. I asked for more guitars, they said no. And I asked for simplicity, and they covered it in flutes! [...] They added strings and – I didn't like them, but I could live with them. But the flute! The first time I heard the album, I cried and it was all because of the flute."