Well... those programs contain a mini database of camera/lens characteristics... If the camera is NOT in that database, the program cannot perform the necessary lens/camera corrections. It's pretty common that newly released cameras aren't included. When that happens, those programs frequently respond by failing to start until an upgrade has been applied to add those new cameras.
That camera is supported in the current version of DXO and if you upgrade, it will work... The 8.5 version, as I recall was given away for free as a trial...
If you want, I'm sure that a DNG file will work. You can convert the D5300 NEF file to a DNG file using anyone of a couple DNG conversion programs, and then Edit the D5300 DNG file using version 8.5