Chess: A single position from the tournament

So I worse than usual in the tournament on Saturday.
I lost a game to Hive account@schamangerbert, he did really outplay me in that game, then we had a return match where he made a
mistake, after this that game went easy.
Apologies to Hive account@schamangerbert, but this is a somewhat common mistake, so I decided to write a post about it.

Black just played Nf6, however this is a big mistake.
The logic might be that black puts pressure on the white center, unfortunately white can win a piece.
Nxf6+, the part about this being a check is the important thing, since when black recaptures the piece on f6 the bishop on f5 is still hanging.