Car stalls at idle- restart difficult

All of a sudden, my car began stalling infrequently at idle; in slow traffic, sitting at a stoplight, stop sign. I put it back in Park and it will restart but it struggles. It is trying to turn over but I usually let it sit for 30 seconds or so then try it again, then it will start. I have put 2 treatments of fuel injector cleaner in it and it seemed to help short-term. It stalled again yesterday as I waited to pull inside the garage! It is a 2003 Nissan Maxima SE with about 95000 mi on it. Can’t be the battery because all lights, etc work and it will eventually restart. I have an appointment to take it in to get looked at tomorrow and I just want to have some leads before the mechanic gives me their opinion. Thanks!! HELP!

The IAC would be a prime suspect.