Is there a reason why the king taking the knight wouldn't be the first move? I don't see what black's following move would be after that
Check out this INSANE tactical puzzle!!!

Is there a reason why the king taking the knight wouldn't be the first move? I don't see what black's following move would be after that
What happens after Kc4?

you can't do Ng3
Why not? What move by black can't lead into a mate in 1 for white?

IK using engines in puzzle solutions is cheating, but the fact that the OP provided no solution and the NM in chat being unsure lead me to try the position in the chess.com analysis board. It claimed M3 was the best with multiple solutions, but no M2.
@BraydenPlaysWithStyle, do you have a real M2 solution?
Is it 1. Nc2/Ng2 Nxc2/Nxg2 2. Qb3#?
If 1. Nc2, I don't see a checkmate in 1 after 1...Nc4. 1. Ng2 may be correct though: if Nc4, Nf4#; if e3 N to anywhere else, Qb3#; if Ke6, Qd6#, if Kc4, Nxe3#; if Ne8, Bf7#; if Nxh5, Qg8#; if Ne6, Nxe3#.
Yeah, I forgot about Ke6 after Nb4+. It's definitely Ng2.