Yes and No. You cannot run them in Nvidia SLI (multiple GPUs) as they need to be identical chips. Example: GTX 1080 + GTX 1080 = Yes, GTX 1080 + GTX 1050 = No. Besides the GTX 1050 doesn't support SLI to start with.
However you can go into the Nvidia control panel and setup the GTX 1050 as a dedicated PhysX card, it should handle this alright but i doubt you'll see a whole lot of performance improvements except the various games that use high amounts of PhysX that would benefit from it. As far as i know Arkham knight, Borderlands and Witcher 3 are good examples of PhysX games. But overall i suggest just selling it or using in a new build since you wouldn't gain much from it and it would be using up space and power that isn't necessarily required. Finally if you need help finding a new GPU, we can help you out just give us an idea of what your running at the moment (Power Supply, Monitor, CPU) and your preferred budget. Hope this helps
Read up more on setting up PhysX cards here > http://www.hardwaresecrets.com/how-to-install-and-configure-a-dedicated-physx-video-card/2/