Both are effective so let's compare.
Chips are far more expensive than sand ($22 for a bale here), are prone to absorb spilt water & uric acid then it stinks, must be completely removed & disposed of when cleaning, and tend to mold and stick to the floor in hard lumps.
Coarse sand is cheap (about $10 a pickup load), allows birds something to scratch in, is a supply of grit, does not absorb and stink, does not need to be removed during cleanings (just a rake and kitty litter scoop) but if it does you can throw it in the driveway, can be cold on bird's feet in the winter but birds roost anyway and can be washed down after cleaning depending on coop floor design.
But you should maybe try them both and see what works for you. Both clean out very easy with a shop vac and a putty knife for the lumps of chips.