It is surprising how many people seem to think you need IAN in order to fly an RNAV appraoch.
In my company we do not even have IAN in our 737's and yet we fly RNAVs daily.
Simply use LNAV/VNAV. You can't use LPV minima, but I tend to say in most than 99% of all cases LNAV/VNAV minima are more than sufficient.