I synced iPod with my MacBook,now iPods empty & 971 songs are missing! how do I find my music?please help

I was hoping to copy my music from my iPod nano to my MacBook because my nano has a bad screen(cracked)& I wanted to update my playlist. my Mac is running Big Sur. all I did was click on sync & all of the sudden I watched my nanos music storage go from 971 to 0.i don't know where it loaded or synced to but now I've got no music.if u might be able to help me figure out either where to look or figure out what happened

I'd really appreciate it, thanks