The Nissan Path

I've searched and read for a few hours and I'm not sure I've found an answer.

I have an '05 w/ new radiator and re-manufactured tranny.
About 10k on the replacement tranny. 110,000 miles

My SES light came on and the same day I started getting a higher pitched whine when I accelerate, usually at high rpm right before it shifts.
It comes and goes and it is worse when it is colder.

I have very little knowledge of cars so I apologize ahead of time.

Is this a transmission issue?
Is it a drive chain issue?
Tensioner issue?

Help appreciated. I checked out youtube videos and I was unable to discern that any of them that I could find where the same as mine.

It's impossible for us to tell you without being hear the noise for ourselves. If it is the timing chain tensioner noise, you'll be able to hear it sitting still and revving the engine to a high RPM. It'll sound similar to a bad P/S pump "whine." You can find YouTube vids that demonstrate the noise, as well.
One thing that would help is if you had the trouble code read, as this might be able to give us an idea of what is going on. If the transmission was a Nissan unit and installed with the last 12 months, I would suggest you get in touch with a Nissan dealer as it's under warranty for 12 months/12000 miles. Even if it's a hair over in time, you might still get them to do something for you (if it is a trans problem) being that it has only 10000 miles on it. If they say they can't, call the Nissan customer service hotline at 1-800-NISSAN-1 and discuss the issue with them; a Nissan reman trans should last more than 10000 miles.