The 3RZ-FE engine is awesome. I had one in my 1995 Tacoma and often miss it. The 5VZ-FE in my current Tacoma has a belt that needs replacing at 90k. Yours has a timing chain and someone correct me if I'm wrong but as far as I know it does not need replacing. As long as you change the oil on a regular basis, which lubricates the chain, you should be fine at this point. Now if you still have the truck in another 100k miles and plan on keeping it you may want to replace it to be safe. For now I would not worry about it.
"If there must be trouble let it be in my day, that my child may have peace." Thomas Paine
2003 Toyota Tacoma DBL Cab TRD
2007 Adventure Trailer Chaser
1987 Toyota 4runner Turbo