Jarrod Bowen had the Irons ahead before Georginio Rutter struck an equaliser in injury-time.
Nuno said afterwards: "It’s really hard to take.
"It's clear (that Brighton’s goal should have been disallowed). It's not that it appears (to be an infringement), it's clear. I saw it, everybody saw it. We cannot understand how they give the goal.
"Everybody saw it. It’s hard to take, really hard to take.
"What’s the point (in seeking an explanation from the match officials)? The game is finished. We have to focus on (Aston) Villa now.
"I think both situations should be checked. I thought it was also handball, don’t you think?
"The support of our fans that make us feel like we were in London, then comes one situation, and so many people see it, it's hard to take.
"We trust (the right decisions will be made). This is the best league in the world. There's not much to say.
"It's hard to speak when you have a group of players so disappointed. We are in a tough position. This game meant a lot to us. The boys worked really hard.
"It's hard to take to go back to London with the point this way."