"I'm That Chick" is a disco song with R&B influences[1][2] The Guardian's Alex Macpherson noted that the R&B element borrowed from 2008 trend in the genre of using a time signature of 44.

[4] PopMatters writer Evan Sawdey wrote "the few times that she is handed a truly effortless stunner on E=MC2, she absolutely knocks it out of the park" with regard to "I'm That Chick" and "Side Effects".

[1] However, Jayanthi Daniels of The New York Sun was critical of "I'm That Chick" as well as "Side Effects", describing them as "throwaway pop tracks" on a hip-hop album.

"[7] Joey Guerra from the Houston Chronicle felt that the "Off the Wall" sample "breathed life" into the track, writing that the only things which are missing are "roller skates and short-shorts".

The triumph of the song is that, when all of our dance-floor divas these days seem to throw one disco-descendant banger on their otherwise hip-hop-hybrid LPs almost out of obligation, 'I'm That Chick' doesn't feel even as tokenistic as Janet's 'Feedback' (which I like more, but only out of context).

[13] Carey later performed "I'm That Chick" alongside several male dancers, opening the song with a spontaneous a cappella of the track's chorus to positive critical response.