trim fat from chicken breasts.  place in ziploc.  add enough salsa to cover breast.  add 2-4 splashes soy sauce, per your taste.  allow to marinade for at least 6 hours.  24 or overnight is best.  heat grill or indoor grill.  grill chicken.  serve with your favorite tortilla chips and more salsa.  Can also serve mexican rice or white rice on the side. 

my friend Justin's mom taught me this when i stayed up there in Sedona.  WAAAAAY easy and SOOOO yummy. 

if you want you can even freeze the chicken in the salsa and soy sauce... seal the baggie up good and it will be nice and flavorful - defrost in a sink filled with water.