"I won't forgive them for what they did yesterday,'' the world No 2 said.
"It's all very well they think I can play catch-up but why should I be on a handicap compared to the other riders?
"It wasn't yesterday that fired me up for the ride today. This is the horse's spatiality and my speciality but, for sure, I was fired up yesterday and I haven't got over it yet. What they did to me yesterday was a disgrace.
"I have expressed it to anyone and everyone who will listen and if they don't want to listen I will still express it to them.
"I expected to go clear and fast today and I expect to jump two clear runs tomorrow. I didn't expect to be handicapped in the dressage.''
Nicholson is known for his short fuse and some believe it's just sour grapes. But for Nicholson, who has never won an individual Olympic medal in his seventh Games, it hurts. He was so confident heading into the competition, he almost expected to win.
He's not out of it entirely, sitting in ninth on 45.00 penalties and just over a rail behind leaders Ingrid Klimke (Germany) and Sara Algotsson Ostholt (Sweden), but gold seems beyond him. The competition has thrown up a few surprises and Nicholson has to believe it produces more tomorrow and the first could come in the vet check in the morning prior to the show jumping phase.
"He's the best jumper I have ever had,'' he said. "Show jumping is one of those things that if you rub a pole a little too hard it falls down and you get four penalties.
"If I ride him like I normally ride and he jumps like he normally jumps, I think we can peg them back over two rides.''
The show jumping will be contested over two rounds. The first counts for both the individual and team's event and the second, for just the top 25 riders, will decide the individual placings.