In their documentary, Simon scolded Chisa for ‘feeling herself too much’ while singing but I honestly LOVE it when she does, it makes the performance so much better when you can feel the passion!
I don't think Simon was referring to her feeling herself too much as a negative thing in and of itself. I think he was seeing it as dangerous for her to sing like that already because she ran the risk of thinking too highly of her singing and potentially becoming complacent way too early. He scolded her for it as a way to humble her and maximize her future development, I'm pretty sure. It has its time and place and this VOX performance was definitely it, I'm sure Simon would agree.
Chisa is an underrated superstar. Shes the whole reason i went deep into XG. After hearing her sing the prechorus in shooting star i was in love. I knew she was special. Add her personality and wow what a genuine human.