Sousa had seen Swansea denied what looked a stonewall penalty against Darren Pratley and then not been given an offside decision which would have prevented the corner from which Forest scored the winner.
The Swansea boss said: "People who make mistakes are only human but what concerns me is that it is happening week by week with us.
"The stadium was in shock when we were not awarded the penalty. Everyone could see that it was but we didn't get what we deserved.
"If the decisions in our games had been the right decisions we would be close to the top of the division by now. It's happening too often and I hope someone can explain the situation to me.
"We are a team playing well, always looking to win games and gaining respect from the opposition but there is nothing we can do when we receive decisions like the ones we did.
"But we need to stand up our heads because we need to feel proud."
The win, which puts Forest back into an automatic promotion spot, came from a Lewis McGugan corner that Swansea felt should have been a free-kick in their favour.
But Chambers arrived at the far post to head home from close range after the otherwise faultless Swansea goalkeeper Dorus De Vries flapped at the corner.
The other flashpoint moment came in the 73rd minute when Chris Cohen bundled over Pratley from a cross by Mark Gower but the referee waved away Swansea's frantic appeals for the spot-kick.
It was a decision that Forest boss Billy Davies admitted would have upset him had he been on the receiving end of it.
He admitted: "I would not have been happy about it but what goes around comes around and we have had decisions go against us in a lot of games.
"On the balance of play I thought we just about deserved the win. We created the better chances.
"We should have gone ahead but Chris Cohen tried not to get his hair dirty when he had the chance to give us the lead.
"It's a big, big win for us and it's a tremendous achievement for this side to be where they are at this point of the season.
"This time last year 75% of them were fighting relegation and they deserve enormous credit for getting this club where it is now."
The one downside for Forest was an early injury to influential skipper Paul McKenna which threatens to take him out of their promotion bid.
Source: Team Talk
Source: Team Talk