Let's check this out,shall we.

She has been trying to be in the music game now for years - I mean, didn't her Lizzy Grant Album come out in 2007 or 08? Has she not been doing gigs? I know a big gig like SNL is nerve wracking, but she seemed to do okay on Jools Holland, which also has a live audience.

Is she is still that nerve-wracked now how is she supposed to advance in the future?

The video is there for all to see - it's a Maida Vale LIVE session for the BBC and Zane Lowe with no 'jiggery pokery' involved and she absolutely smashed it so who knows what happens on TV? Jools is different in the sense that the acts are there all day mingling so I'm assuming there's less stress/pressure and lots more camaraderie involved. I'm sure she will conquer her nerves and deliver on live TV. Let's be honest, if she had performed like this on SNL how different the headlines would have been...

Oh wow, that was good.

I'd say her problem on SNL was both nerves and inexperience. Does she have stage fright? I know she described herself as a studio singer and her vocals in the clip posted above were good... but that was a different situation as well so she probably just felt more comfortable. I'll say this again, I think she will get better with time.