Noob's Brilliant move makes eval bar go down

So I was really happy to finally beat the SonicFox bot (I'm below 1000 elo) and I was pleasantly surprised when I got my first brilliant move ever. However, when trying to understand why it was brilliant, I realized it was probably a blunder and should be marked with (??) rather than (!!). The move in question is this one:

So basically I'm threatening to go to C7 with my knight, forking the king and the rook, ignoring the threat on my other knight. The problem is, though, my 900 elo brain missed the fact that C7 is already protected by the knight on A6, and even then black could have just moved the rook I guess.

If that wasn't enough, the eval bar dropped from +0.8 to +0.5 after this move. I remember reading that brilliant and great moves on chess.com should never leave you in a worse position...so...is there actually any brilliancy in that move?

But how would the move above be a good sacrifice? I don't see how it makes my position better.

Well if he took your e5 knight, you could have forked the king and queen. You would win his queen.

You weren't really threatening Nc7+ because he would have taken your knight with his knight on a6.

Your basic threat is Nd6+ forking king and queen, not Nc7+.
Nb5 is certainly a good move, but neither "brilliant", nor necessarily best. The simple retreat Nf3 leaves Black with a few rather serious problems to solve.

Oh, so that's why! Thanks for explaining.

Interesting that I got a "brilliant" move with the wrong idea. Oh well. I'll keep on improving, hopefully I'll be able to get past the 1000 elo barrier soon.