Firstly, please make sure that your PC meets the Thronebreaker: The Witcher Tales System Requirements.
If the requirements are met please make sure that all applications non essential for your pc are turned off/disabled. This includes antivirus/antimalware programs.
If that won't help please check if your PC is malware/virus free - those may sometimes cause crashes.
You may also try verifying game files, as described in the corresponding article:
GOG Galaxy
Steam
If any of the above won't help, reinstall your GPU drivers. To do so completely follow these steps:
Please be aware that sometimes installing older drivers might help with crashing.