Applying to Harvard, Columbia, SMU, University of Oklahoma, University of New Mexico, and Tulsa Law.
Harvard and Columbia = 0% chance unless you want to retake the LSAT or have an incredible overcoming hardship story on top of being a Native American
University of Oklahoma = ~85% chance, they have a low overall bar for admittance to their law school, but they also specialize in pretty much two things: (1) petrolium related fields of legal practice **mostly going to be property rights** and (2) native law. Since you want to work in native law, OU would be an ideal destination for you since they are one of only a few schools that actually donate resources to this field of study, you have many different tribes that have tribal seats in Oklahoma for obvious reasons, and they are one of only a handfull of schools that have a Native Law Journal...
UNM - similar to Oklahoma, but OU would probably be your better option.
Tulsa - same boat as OU, you have similar admission chances but OU is more bang for your buck with what you want to study, unless you get scholarship $$$. Based on friends I have had or people I have known that have gone to both law schools, I think Tulsa and OU hold most of their scholarship money for people with LSATs in the mid 160s though.
SMU - chances are probably more 50/50.... but with you wanting to practice Native Law there isn't any real point in you going to SMU. It is almost exclusively a business-minded private law school, it will be much more expensive (living costs + tuition), and won't significantly increase your job outlook.
Hope that helps. Sorry to be harsh about the Harvard/Columbia chances, but the bottom line is if you do not want to retake your LSAT and sit out a cycle you will not have a chance.
EDIT: Also, I am an AI/NA applying this cycle and have done a lot of research into what kind of URM bump there is for native applicants. From what I have read, the bump is similar to that of an AA, so it will do a lot for your but it won't part the seas. If it is indicative/helpful at all, you can find my admission outcomes so far on
http://www.lawschoolnumbers.com under the same username.