Two different drivers named in your two crashes but both possibly = the same route cause (nvlddmkm.sys and HIDCLASS.SYS) are the drivers concerned.
Dell states the following regarding the Dell XPS 15 L502X;
Product not tested for Windows 10 upgrade
Dell is not testing or developing Windows 10 drivers for this product. If you choose to upgrade, some features, applications, and connected devices may not work as expected.
This is telling us that you upgraded from a previous OS, when you did so did you also reinstall the latest available drivers for MB and starting with the chipset first, if you do not follow the steps suggested by Dell you will get problems, see How to reinstall drivers in the correct order
here and the appropriate downloads
here
The following is info only, the USB mouse driver mouhid.sys failed to load in your second crash dump, since XP Windows has used generic mouse drivers cutting out the need for any third party drivers, the mouhid.sys is though associated with the HIDCLASS.SYS related crash and potentially caused by incorrect/incompatible driver installation after upgrading to Windows 10.