Nitronic 60 is essentially a non galling SS s;highly stronger and about as corrosion resistant as 304 SS. We have used numerous Nitronic 60 Helicoils with great success on Austenitic SS components with Austenitic fasteners.
The kolsterising treatment imparts a hard case on Austenitic SS. This too is anti galling though is fairly brittle compared to the base metal. Though I haven't used it wouldn't consider a strong candidate for a Helicoil.
A Kolsterised sleeve running against a Nitronic sleeve is an excellent combination for use in pumps. It's use in this type rotating environment is where Kolsterising excels.