First of all I searched...
I have a 99 se-l with 144k miles. I'm getting what seems to be a very light timing chain noise. I tried to make a video but it's not loud enough to hear. I thought the 99's had improved timing chain components to prevent this from happening. With only 144k on what I'm presuming is the original motor this seems very odd. Opinions?

 

Not weird at all, although 4th gen have better components compared to 6th gen, it still happens.
I have a 5th gen and bought the car with that issue already, I thought it was a tensioner, but replacement of the piece didn't help, while I was there, i checked the guide and that what causes chatter in my case.

You can try replacing the tensioner, but if you can barely catch the noise - leave it at that for now. Once it gets louder - you could replace the tensioner and see if that was it

EDIT: by saying I have 5th gen - I have 3.0 DE-K
Seen few of these reach complete failure at over 160k, two are sitting at my friends shop

 

I've of them going a long time with the noise. But I know replacing the tensioner is a waste of time because it's usually the guides.

 

listen man, i have had the rattle noise since i bought the car at 129,000 miles and now im at 252,000 and a nice loud rattle especially now that its getting colder. i add bg moa to help with the viscosity, and i have had a timing cover leak since 190,000 and shes still running strong. keep the fluids fresh, especially the oil, and when it rattles and doesn't go away, that's when you gotta worry.

 

Sometimes it's constant sometimes it's not. Lol I think my timing cover is already leaking. This car is gonna suck me dry.