Kamara joined last month on loan from Major League Soccer club Sporting Kansas City and his introduction just before the hour breathed new life into the Canaries, who were trailing to a first-half goal from Leon Osman.
"Kei is a different type of player to whom we have up front and we are delighted for him," said Hughton, who had started with both Holt and January signing Luciano Becchio in attack.
"He had been here to England before (on trial at Stoke), but these things are all about timings and it was right for us. He has that ability to get beyond and is good in the air, he gives us good possibilities."
Hughton added: "Once you are 1-0 down and you get back to 1-1, you have to be honest and say you settle for that. But the lads wanted something different and showed great drive and determination to get the winner."
Defeat was, though, somewhat harsh on Everton, who had been the better side for long spells, with Marouane Fellaini central to all their attacking threat.
Everton manager David Moyes bemoaned his side's lack of a killer instinct in the second half, when they could have put the game out of reach.
"We had controlled the game, but were wasteful in the second half when we had chances to get another goal, and we were always going to be put under pressure at the end," he said.
"I cannot understand why he plays three minutes and 20 seconds for the stoppage time, but he has got that discretion, although I disagree with it.
"We passed it well enough and tried to do the right things, but we were not good enough in the final third - but one thing is for sure, we did not deserve to lose."