Quoted from Aladdin:You guys debate, Imma gonna watch this video again. I must admit, I didn't know who St. Vincent was prior to this thread.
Here she is performing with Nirvana at their R&R Hall of Fame induction in 2014 -
… playing her Harmony Bobkat. (err probably prerecorded)
You can see rest of the bad ass Nirvana tribute here with Joan Jett, Lorde, and Kim Gordon (sonic youth).