Beginner -why is this site saying e5 is best?

I just recently got into chess and decided to use an analysis site. I moved kc6 but it said pawn to e5 would be best. Why? When knight can basically get a free pawn possibly 2. Which I did

Check out this #chess game: ullylsf vs BigxRedxHusker - https://www.chess.com/live/game/148538183292