After 8. Nxe5, 8... Re8 wins back the d4 pawn with an attack.
Kings Indian question

e5 is guarded by the g7-bishop indirectly. In all cases black wins the pawn back with Nxe4 with the advantage.

There is one line where black willingly sacrifices the e5 pawn, as in this game
http://www.chessgames.com/perl/chessgame?gid=1281354
I have a confusing question. After looking at the GMs play the Kings Indian defense I am confused why they do the 6.. e5 move with nothing guarding that square. Now no white players have taken e5 in all the games I have looked at. The only thing I can think of is a knight move uncovering the bishop. Thanks for the comments ahead of time..
While I was doing the diagram I figured out why black is not afraid of the e5 pawn being taken. But I will post this anyway incase anyone finds it useful.