Terrible clicking noise coming from passenger side engine. Any ideas?

Oil level is normal.

https://www.youtube.com/watch?v=4ZAyg3_ySsw&feature=youtu.be
https://www.youtube.com/watch?v=AlDqYfzvzio&feature=youtu.be

Something is rattling pretty good. Have you checked your heat shields and exhaust components for loose stuff? I'm guessing a heat shield near the manifold and or primary catalytic converter. At least, that is my hope. Otherwise, it really sounds like it could be a problem with the exhaust valves and I would hope it's not that. You get regular oil changes or just top it off every now and then?

If you have a current warranty or extended warranty, I think you should bring it in.

Search Versa piston slap. It's a common characteristic to the Versa engine.

I'd be cautious taking advice from single posters with doomsday diagnoses. I wouldn't discount it immediately, but web MD said I was dying just because of a sore throat symptom... grain of salt.

Uh, that kinda sounds like internal noise to me, but not the best of vids there.

If piston slap it didn't show up instantly, took a bit of time to get louder. One way to tell................could be something as whacky as piston lightly hitting head from a dead rod bearing too.