Disso queen Laura Wasser filed her blistering response to Christine's request ... explaining the fees would supposedly be incurred for a mini-trial over one issue in the prenup -- whether her waiver of spousal support is enforceable.

Christine's lawyers say it will take $885k to make their case -- and they want Kevin to foot the bill -- but Wasser fired back that based on hourly rates, Christine's legal team would have to put in 1,106 hours to justify the fee.

Wasser calls Christine's ask "nothing short of outrageous," also noting the judge has already indicated the prenup is enforceable, so the road Christine's going down is a dead end.

Christine has not only lost most of the legal battles in the divorce, she's actually lost more than if she had settled with Kevin. For example, she originally wanted $248k a month in child support, which Kevin rejected and claimed the reasonable amount was $63k. Nevertheless, he offered to pay her $75k a month, but Christine rejected that offer and duked it out in court. In the end, the judge said $63k was the appropriate amount.

Wasser says Kevin's already paid Christine $300k in legal fees, and also allegedly took $105k from Kevin's accounts to feed her legal team.

And there's this ... if Christine challenges the prenup and loses, she'll have to return more than a million bucks Kevin gave her and also pay his lawyer's fees.