I think she means playing the open C chord form moved up. Open strings are pretty much key of G (the 1 and 5 power chord are there on the G and D strings). I find it odd that people go to such great effort to construct the chop chords and then usually only use 2 or 3 strings. On most songs, failing to completely mute the E string on a chop sounds pretty bad to my ears (and my instrucor and many of my books tell me not to sound it on a chop).
"First you master your instrument, then you master the music, then you forget about all that ... and just play"
Charlie "Bird" Parker