Pour 1/2 the jar of salsa on the bottom of your slow cooker.
Lay uncooked chicken breasts on top of the salsa.
Dump the corn, beans, and pineapple on top of the chicken.
Pour the remaining salsa on top of the mixture.
Cook on low for 6-8 hours or on high 3-4.
You can serve in your favorite taco shell (hard or soft) and use your desired toppings. This also works well on top of rice.