if you play dxe right away, he can recapture with the N, which threatens your queen, and the initiative turns in his favor.
however, if you play Nde5, it opens up the rook on the queen (sort of an xray attack), and makes him find something to do. it also threatens the d3 square, which he'll have to defend because a N that far into his camp is extremely uncomfortable.
so, he may have to exchange his strong bishop for your N, which is very good for you.
I played a blitz game(10 min per side) recently where above position came after 18 moves.
Upon computer analysis,I see that computer wants me to play Nde5.Not only that it suggests this line 18..Nde5 19. f4 dxe4 20. fxe5 Qxe3 and I end up losing my knight.
Why should I play Nde5 here...why not 18..dxe4 straightaway?
I am sure I am missing something here.Can someone help?