Many installed apps crash after OTA update to Android 4.2
If your device is rooted, and you have a custom recovery installed: Wipe the dalvik cache. Next boot will take a little longer (as the Dalvik cache has to be rebuilt), but the problem should be gone.

If the above is not an option, you could try to backup the affecgted apps and their data using e.g. Helium Backup, then uninstall the apps, and restore them (including their data) from their backup. This way their Dalvik cache would be rebuilt as well, you don't lose your data, and Helium can do that in a batch-process to save you a bunch of clicks.