Hello there,
On my fleet of 737 the Left IRS powers the ISFD so youd have to lose the L IRS for this failure then go to appropriate checklist.
You may end up not RVSM approved and to fly manually a long way if the FAult doesnt clear.
I would return.
If you lose the RMI (ac stby bus powered) you have no back up for radio navigation if you end up with Both Gen failure (bad day huh).
I would continue if weather is reasonable at destination and you are under radar control all the time especially in descent/approach phase.
Both are NOGO items on the ground.