white is up 2 pieces, i dont really see how he can loose
Private Property: Trespassers beware!

You're right, White is highly unlikely to lose, but Black isn't completely finished yet and would be quite able to put up a fight for at least another 15 moves. He could also attempt something offensive and risky like Kd3.
With White's Queen's Rook locked in the corner (especially after Kb3) and Bishop hanging on h8 it is effectively King and Knight against Two Knights and a Rook, which is obviously a disadvantage for Black, but not one worth resigning over immediately.
Anyway, the move to be found is one that forces mate in a few moves and shortens the game noticeably for White, notice how the pretext to the puzzle doesn't ask you to play for Black and win! (funnily enough...)

Cheers Luke, you using my theme yet? 'The persistence of Memory' take a look, it's quite easy on the eye.
On the note of self advertising; check out my other blogs!
p.s. I didn't make this, it came from an online game I played, just thought it might be interesting as a puzzle
Black is in a losing position, but lacks the pressure of white on the offensive at his heels. He decides to venture a little too far behind enemy lines with 1...Kc4.
White may not be fully on the offensive yet, but he is no pushover. How will he punish this transgression with deadly effect?