Here's a mix I use:
Mexican Seasoning Mix
¼ c chili powder
¼ c cumin
¼ c ground coriander
¼ c granulated garlic
1/8 c ground black pepper
1/8 c red pepper flakes
1 T salt
Blend together and store in an airtight container.
I take a chicken breast, pound it out kind of thin, and put it in a ziplock baggie. I mix a tablespoon of the seasoning mix with 2 T of veggie oil and the juice of half a lime. I pour this into the baggie, and make sure that the marinade is in contact with the entire breast by squeezing out as much air as I can. Marinade in the frige for 30 minutes, then grill until done. Slice the chicken, arrange on the nacho chips, cover with cheese and any other goodies, then under a broiler until the cheese melts.