BlingBling1249 wrote:
Game played between me and Nelson (I am white)
It's because of how "Brilliant" moves are defined. You are seemingly sacrificing the knight, but it cannot be taken or else Black gets checkmated. And if Black doesn't take the knight, you are simply winning anyway.
"Brilliant Moves must... sacrifice material in some way and must be the best, or nearly the best, move in a position."
More information about the current Brilliant move algorithm: https://www.chess.com/blog/Alramech/the-new-brilliant-move-algorithm-in-action
Game played between me and Nelson (I am white)