If it is a temp problem it should be easy to check. just run HWinfo or similar software to see what the peak temps are when you get the issue. HWInfo and HWMonitor will show max, min and average so you dont need to sit and look at the software at all times.
Not sure if its relevant but in BF4 and BF1 I remember people playing on laptop got issues with the game starting to use the IGPU. Meaning it suddenly started using the Intel GPU instead of the NVIDIA/AMD gpu. Since the Intel gpu isn't good enough to run the game the results was very low fps.
Maybe try to force the game to use the Nvidia card. It can be done in nvidia control panel but if that doesnt work you have to do it in the bios.