I believe there is no consensus on the board as to whether other beta blockers work as well as Propranolol for the SN method.
You would probably want to read up on your substitute medication and see if it specifically targets tachycardia, which is the symptom SN causes and Propranolol reduces. You would also want to check time to onset of the medication, vs that of Propranolol, to know when to take it as part of your protocol.
Finally, plug it and other meds (including SN) into the drugs.com interaction checker and see if there are any significant interactions reported.