When the CWM and TWRP for the Nokia X got available for download, it was just a matter of days for the CM10 a k a cyanogen mod to get ported. Today is that day and you can install it.
Get the ROM from here. To install it, wipe system, data, cache, dalvik cache and flash the firmware. You will also require gapps which you can flash from here.
Cyanogen Mod gets more frequent updates compared to the close-to-stock AOSP ROM that also got available for download earlier today.
We also suggest you to keep an eye on this thread for further updates to CM10 development for Nokia X.