In a 4 quart slow-cooker whisk the broth and taco seasoning together. Stir in the onion and garlic.
Season the chicken with salt and pepper and nestle them into the slow-cooker.
Cook 4 hours on high or 6 - 8 on low.
Remove the chicken breasts to a cutting board and let them sit for 5 - 10 minutes.
Cut or shred the chicken into bite-sized pieces. Add them back to the slow-cooker and toss with the juices.
If the chicken is very juicy let it cook on high with the lid off to evaporate some of it off.
On a large baking sheet or 2 medium sheets lay the tortilla chips out.
Drop spoonfuls of the chicken over the chips. Sprinkle with cheese.
Bake until the cheese is melted and the chips are hot 10 - 15 minutes.
Top with the olives, tomatoes and scallions plus any other toppings you like.
Serve with sour cream, guacamole and/or salsa.