It appears that the 2017 Bolt and the 2017-2019 Volt use the same seat base /slider track assembly #13514824. This strongly implies that the seats from a late model Volt will drop right into a Bolt. I have ridden many times in a 17 Volt and the seats are worlds better. You can head to your local Carmax or Chevy dealer and try them out.
If this is accurate, the considerations are:
Color of the cloth/leather is different - seat skins do not appear to be swappable.
The Volt seat has an integrated airbag that is not required in Bolt. It could be removed and replaced with a foam block or left unconnected.
The width available between the seat and the center console needs to be confirmed
The seat belt anchor comes with the seat - it should be compatible but needs to be checked
The electrical connector for seat heating and occupancy sensor might be different
The electrical signals (open/closed, resistance etc) may need to be confirmed before using seat heat etc.
Used seats are readily available on the internet.
While my family owns both a Bolt and a 17 Volt, the latter is in the shop for a few weeks after getting T boned. Does anyone else have interest or access to look into this?