Nifong can't keep the SANE report OUT. If he fails to introduce it, the defense will. He can only choose not to introduce it.
The prosecutor cannot by fiat keep out the SANE report. He has to introduce and try to minimize the problems for his side of the case. He would not want to pass the witness to the defense without having tried to take the sting out of the bad spots. Otherwise, the defense is able to first disclose the problems to the jury, and that's good for the defense.
Don't count on it. Nifong's case in chief is already in shambles, and Crystal's story hinges entirely on the SANE report. My guess is that he will simply authenticate the report with little or no further questions. At this point, he might as well throw the SANE nurse under the bus because every conceivable witness (from Crystal to every police officer to the Durham Access Center to the Duke police and on and on) has to be discredited in whole or in part. This prosecution is a sick joke.
His case in chief will last about an hour, consisting of the SANE report, Crystal's newest version of events and in-court ID, the infamous DNA on the fake fingernail, and that's about it. Probably exactly what he told the grand jury. I still think there is a fair chance this will never get to trial because eventually a real court will get hold of this.