Jacob has won the Grade 1 contest at Haydock three times aboard the grey Bristol De Mai and will be on last season's Cheltenham Gold Cup runner-up this weekend after an encouraging schooling session at Ditcheat on Monday morning, with Cobden required at Ascot.
Speaking on a press call organised by The Jockey Club, Nicholls said: "Bryan (Drew) who owns Bravemansgame is very keen to run and he has come out of that race (Charlie Hall Chase at Wetherby) very, very well.
"He's that much older now and it's another month to Kempton (King George). And it (the Betfair Chase) is a valuable race, so if the ground's not too bad we'll run.
"Daryl has won the race three times and he's got the experience and came to ride the horse out this morning.
"Harry (Cobden) is going to go to Ascot, he's got six rides there including Pic D'Orhy and several others. That's the decision we've made and that's what Bryan's happy with.
"We've always had Pic D'Orhy in mind going to Ascot and Johnny (de la Hey, owner) has 15 or 16 very nice horses in training with us and needs looking after. And Harry is very important to Pic D'Orhy, possibly more so than for Bravemansgame.
"Sometimes when you have big meetings on a Saturday you have to make these decisions and I spoke to Bryan in depth and Harry has six good rides on Saturday, it's an easy decision to get someone else to ride Bravemansgame.
"There's no question he'd go back to being Harry's ride (in future) - Harry is stable jockey but he can't be in two places on the same day, of course he'll ride him again."
In terms of Bravemansgame's well-being going into a potential clash with the Nicky Henderson-trained Shishkin and last year's winner Protektorat, Nicholls expects improvement.
He said: "Bravemansgame has taken a large step forward since Wetherby, he hadn't been for a racecourse gallop or anything as we knew there were bigger targets down the road. So he has come on enormously and he looks great.
"He's run well in the Gold Cup and is a high-class horse, he probably should be favourite really. It's probably because we were a little bit negative about going there after Wetherby. Let's just hope for the dry forecast. I expect by Saturday it could be soft, good to soft in places but it's never quite as bad as it was when it was on the original track there."
Jacob said on Monday's Nick Luck Daily podcast: "It's hugely exciting, me and Paul have always got on great. For many years I've been riding out for Paul and down at Ditcheat now and again.
"He was lovely today, those special horses have a way of going about things. He's very neat and very powerful, he's very well balanced and professional. I took quite a few jumps going around the ring there this morning and it was a real buzz. It's really exciting, even to have the opportunity to sit on him at home there this morning. I was like a kid going into a candy shop for the first time.
"Hopefully if the weather is right and it might stay dry for the week, he might line up in the race at Haydock on Saturday."
The Venetia Williams-trained Royale Pagaille, Lucinda Russell's Grand National hero Corach Rambler and Minella Drama (Donald McCain) complete a list of six possible runners for Saturday's big race, due off at 3.00.
Betfair spokesperson Barry Orr said: "Bravemansgame and Protektorat are inseparable at the top of the market, but Shishkin is a fascinating addition and while his trainer is on watching watch, hopefully all six stand their ground and we have a excellent renewal of the great race."
