I'm not sure Nintendo will go that way. Not for the near future anyways. Sure, 3DS had the New 3DS with enhanced processing power, but this was mostly unused. Not sure what we would gain from a more powerful chipset.
I can see though other directions for a mid-life refresh:
- revision for better portability: bigger battery, smaller screen without bezels (but same joycons which may be bigger than the switch), chipset with same power but less consumption
- bigger screen version of the switch: the opposite of the above with an even bigger portable screen
- docks with additional functionality: 4K-dock with upscaling for instance