Brilliant move but why?
Because if you move your Knight away
You get back row checkmated.
good point
I gives it a brilliancy because you're recognizing that giving up the knight is necessary to prevent losing. I personally disagree with the annotation, because it's not so much a found sacrifice as it is the only playable follow-up to your Bd3 blunder the move prior. After Bd3 the game is completely equal, and giving up the knight is just the only way to not get mated.
To be clear I don't mean that brilliancies have to be winning, I mean that I don't think they should be forced moves. Good job anyways.