What is the best way to cook chicken that will be used in enchiladas?

If you're using boneless you could rough chop the chicken, coat them in spices and saute them in the pan. Or even with bone-in meat, just de-bone and do the same. Also you could season and bake the chicken in the oven. Or slow-cook the chicken and spices in a slow-cooker, the meat will be tender and delicious. :)