The iPod Nano (stylized and marketed as iPod nano) is a portable media player designed and marketed by Apple Inc. The first generation model was introduced on September 7, 2005, as a replacement for the iPod Mini, using flash memory for storage. The iPod Nano went through several differing models, or generations, since its introduction. Apple discontinued the iPod Nano on July 27, 2017, citing lack of consumer interest in the product resulting in poor sales.

Based on this passage, when did the first ipod nano come out? Let's give stream of consciousness first:
To answer this question, we should know that: The first generation model was introduced on September 7, 2005, as a replacement for the iPod Mini, using flash memory for storage.
So, the final answer is September 7 , 2005.