Could a state implement IRV in the presidential election?

Is there anything in law to prevent a single state from using instant run-off voting (IRV) to determine who will get its electoral votes in a presidential election, even if other states don't follow suit? For those who don't know, IRV allows voters to indicate a first choice, second choice, etc. This would allow someone to, for instance, indicate Nader as their first choice and the Democratic nominee as their second choice, if they wanted to, so they could vote for Nader without worrying that their vote would contribute to throwing the race to the Republican. Since I might well vote for McCain myself, my interest is more about the principle that you'd have to get 50% of a state's voters to support you, at least at some level, to get the state's electoral votes.