When I replaced my ikey module I had to reprogram the keys. The mobile locksmith I called was not able to do it properly, I couldnt use the remote lock/unlock or have the key in my pocket when starting the car. But he was able to get the keys to a state that they would at least start the car if I put them in the doghouse. That was good enough to get the car driving which was most important, and later I took the car to a dealership and they were able to reprogram the keys no problem and get all functionality working. I told the dealer upfront when making the appointment what the issue I was having was, how it all started, and that I replaced the iKey module myself as the repair, and needed keys reprogrammed for the new module. The dealership did not give me any issues at all, and the key reprogramming was quick, about 30 minutes at the dealer. Most of that time was waiting on them to actually take the car back.
I know many 3rd party key programmers say they work with Infiniti and all that, but your experience could be hit or miss. At the very least, it was still cheaper to pay the mobile locksmith $60 and then pay the dealer $100 to do the job again properly than it would have been to pay for a tow ($200) and then the dealer on top. I think normally the dealer costs $200 for both keys though, pretty sure they normally charge $100 per key. I have a great relationship with my dealer service people though, both one of their service reps and the head of the department I have known for 12 years now. So they gave me the price of 1 key to do them both since they know it takes only 1 minute longer to do the second key if they are already doing the first one.