Is this an exam question or one of those "Here's five things the essay might be about?" If so, you're not alone in you confusion; that's a terrible question for any teacher to be asking. The idea of chiefdoms vs. states is outdated and hails back to social evolutionary theory from the later 1800s. It's most certainly not a dichotomy, and there was never even a single, unified Maya polity that could be labeled as either.

If that is the question you must answer though, just pick a side and go a with it. Consider things like the extent of territorial control of Maya kings, how much power they had over citizens, the composition of their nobles and beuaracracy, the transfer of power between rulers, the interactions and relations of various Maya cities, and the distance and interactions betweens elites and commoners. From there, compare the ascpects to known examples of chiefdoms or states to prove your point. And maybe mention why it's outdated that you should even be arguing your point.

(I'd give a more exact answer, but hesitant if it's a homework/test thing)