This is the app Chris is referring to:
Though I can't locate the setting to turn off NFC. Probably will need a third party plugin. Give me some time to explore.
Going back to the issue where the keyboard is interrupted - I can't seem to recreate the issue on the Samsung S4. I tried the "NFC ReTag Free" (which I do not like the notification which appears after every read), and the "NFC for Tasker" (which I found while exploring the Tasker plugins, totally silent. Tasker not required if you just wish to test it. Nothing to configure as well). Looks like different phone react differently to the NFC tag?
Edit: Turning on and off NFC requires a rooted device. If your Android is not rooted, Tasker will not be able to help much in this case.