Bony's brace gave the Swans a vital win after a poor run of form had seen them win just one of their previous 12 games in all competitions.
The Ivory Coast international cancelled out the Magpie's opener and held his nerve to score a 92nd-minute winner from the penalty spot to deliver three points.
Monk heaped praise on the striker, claiming that he has "stepped up to the plate" for the club this season.
"He's been great, Bony. Obviously with Michu ... having an indifferent season with niggly injuries, Bony has stepped up to the plate." Monk told reporters. "You can't complain [about] someone that gets 20-plus goals a season in his first season here.
"It's not just that. He's a massive character in our changing room. He works so hard every day, he pushes everyone else. If he doesn't score, he is a strength. He's a presence up front and he can be a handful without scoring goals.
"It's even better when he does add goals to it, like you saw here. He deserves all the credit. He's been brilliant for us and he can only get better."
Bony, who joined Swansea from Vitesse Arnhem last summer, has scored 23 goals in all competitions this season.