The 76th-minute strike was one of only a handful of highlights from a dull encounter at the City Ground, but that did not concern McCarthy, whose side are now within six games of promotion to the Premier League.
"It's just a matter of getting the points," said the Wolves manager.
"It's not been a great game. Neither keeper has been stopping shots, we've tried to win the game and we've managed to do it.
"We set off with an attacking team and we put subs on and we got the goal that mattered."
He added: "But we're a million miles away, let me tell you. We've won this today and we'll enjoy it."
The late winner certainly had ramifications at both ends of the table.
Wolves are five points clear of second-placed Birmingham after they could only manage a 1-1 draw at home to relegation-threatened Norwich.
And that impressive point for the Canaries means Forest are now two points from safety, remaining third from bottom. Both sides will enter the international break looking to focus their efforts for a final push, but all the attention in the race for promotion will turn to St Andrews when the action resumes when Wolves meet Blues in a crunch clash.
"It's great to have 16 days off although the team we're playing (Birmingham) have got the same 16 days off as well," added McCarthy.
"It means we will not be sat chewing and grinding our teeth wondering what might have been had we not won the game.
"They can go and look at the league and forget about football for a few days.
"It's a nice feeling to have time off having won the last game."
Opposite number Billy Davies felt his Forest side deserved at least a share of the spoils from the encounter and admitted the game looked to be heading towards a stalemate until Kightly's winner.
"We probably deserved a point. I thought our attitude was first class and I thought our effort was first class," he said.
"But having said that, I don't think we created enough. I think they had six shots, we had four. They had two corners and we had three.
"It had 0-0 written all over it and we just didn't do enough to create some chances on our own but, certainly, lots of positives.
"It was a fantastic effort from the players, I was very proud of the way they responded to the last match (a 5-0 defeat at Burnley)."
Davies also reserved special praise for man of the match centre-back Wes Morgan.
"His performance was immense - colossal in my opinion," added the Forest boss.
"That's the type of character we need at this football club."