People talk about these "iconic performances" so seriously, but I can honestly say I never knew what any of the performances in the OP were before ATRL, and I really doubt their "impact", "iconic-ness" etc ventures out far beyond stan culture.
But no, I don't think she really has one.
According to Google its "Stay" at the Grammys but I don't really think it's one that stan culture will remember for years to come.
EDIT: I knew of the Britney/Madonna kiss but I wouldn't have been able to tell you what performance it was, or what award show it was for.