Complex sentence: Nico moved on after the band severed its relationship with Andy Warhol, and recording began on their second album in September 1967, "White Light/White Heat", with Tom Wilson as producer.
Split into simpler sentences: Nico moved on after the band severed its relationship with Andy Warhol. In September 1967, the Velvet Underground began recording their second album, "White Light/White Heat", with Tom Wilson as producer.