NO, It has a timing chain and gears and the odds of it being bad on that year is ZERO. You have something else wrong if it won't run are run right.
It has a timing chain.
The 2003 Chevy Tahoe (both the 4.8 and 5.3L engines) have a timing chain, not a belt.
chain
It has a timing chain and gears. NO BELT.
The engine in that vehicle doesn't have a timing belt.
It has a timing chain and gears. NO timing belt.
It has timing chain and gears. NO belt.
That year and engine size does not have a timing belt. It has a chain and gears
Timing chain
It has a chain and not a belt. No maintenance required.
First of all, It has a timing chain not a timing belt. No need to change the timing chain and gears. They will last the life of the engine.
4.3 has a chain