I've done nose work and IPO. I also train my work dogs for article searches, hard surface scent discrimination tracking and detection work. Dogs with proper training and the proper drives should have no issue transferring from one discipline to another.
With our patrol dogs, we run tracks to a building, where the dog has to find the correct entry point, the door or window that the track layer entered. Along the track articles may be placed and the dog has to indicate. Once the dog finds the entry point into the building, he has to enter and do a building search and then fight and apprehend a bad guy. The fight will be stressful and challenging. We will have narcotics set out in the building as well as distractors and the dog must ignore the narcotics aids and focus on the search for the man. After the fight, we will then direct our spun up dogs to do a narcotics search. The dogs are in drive to fight, gassed after the track and the bite work and must change gears to now do detection work. It's a matter of changing the dog's mindset and getting it on the task at hand.
Doing nose work and IPO at the same time is generally not a problem. One issue that can come up is the amount of time needed to train all the various disciplines. IPO takes a sizable commitment and so does nose work. I'd say IPO is more time intensive. If you do not have the time to commit to one sport, then trying to do two sports clearly won't work.
I do not see any issues with IPO tracking and nose work, quite the opposite. Handlers that do detection work are generally better tracking dog handlers. Because they learn to read their dog's body language and cues better. Articles are a separate exercise and need to be trained off the track. A dog trained in detection work should not start searching for articles or a "find" when told to track. This is a training issue that needs to be addressed in tracking. When starting a track the dog needs to be dialed in to the task at hand and not going off task to perform something else. IPO tracking is easy, it really is easy. The training tracks teach the dog the style we want the dogs to track in. Once at the flag, the trained tracking ritual should kick in. If the dog is distracted, not focused or in a tracking "mindset," simply do not start the track. Get the dog in the proper frame of mind for the task at hand.
Nose work will enhance your dog's tracking and your ability to work, read and handle your dog. Just have enough training time to devote to the various activities.
JMO