The commission read reports from referee Robert Jones and fourth official Anthony Taylor, who said Nuno and Gibbs-White swore at them following the midfielder's red card.
Nuno was also said to have "gesticulated aggressively" at Jones.
However, the statements added that Nuno apologised to the officials after the game. Both men wrote letters of apology to the commission and gave oral submissions.
The commission believed Gibbs-White's remorse and assertion that it would not happen again to be "genuine", offering enough mitigation for the standard two-game ban for being sent off for foul and abusive language to be reduced to one.
The commission praised Nuno for his honesty, even if it did not always help his case, with the former Wolves boss "stopping short of saying it would not happen again".
It said a one-match ban would have been appropriate had it not been for two previous incidents of misconduct, including a suspended one-match ban for comments following Forest's 2-0 defeat by Everton in April.
Therefore a two-match ban, plus activating the one-match suspended ban, was issued.