I'm not sure why the tabs for this song seem to like Em as the starting chord.
I am hearing all major chord, which means it's not Em-D-C, but instead G-D-C.
The first chord is definitely going from note A to note B (e string: fret 5 to 7), so
the other tabs are already wrong. Whether or not these are the exact inversions I can't
say, but the following sounds dead on to me.
[ Tab from: http://www.guitaretab.com/n/nelly/258489.html ]
Anyway, this is what I am hearing:
G D C
|--5/7-7-7---0h2-2-2-------------|
|--7/8-8-8---3---3-3---3/5-5-5---|
|--5/7-7-7---2---2-2---2/5-5-5---|
|------------------------5-5-5---|
|--------------------------------|
|--------------------------------|
For the G chord, I just bar the top 3 strings with my first finger,
and then use my third finger to play the B string notes.