@Jason7373 Yes. You can use third party materials with the Ultimaker S5. You will need to input a new material profile in Cura to record your settings.
I have that printer. Love it for PLA. Love it for the PLA/PHA blend. ABS? Well, not so much. ABS in all forms hates me and my Ultimaker.Is it a requirement for you to print ABS?-Chris
No. You cannot just replace the nozzle. You have to change the entire print core. Currently Ultimaker does not sell cores with stainless steel nozzles.