Warm the oil in a large skillet over medium high heat.
Add the onion and sauté until softened, about five minutes.
Add the cumin and cook for one minute more.
Add the chicken and cook, breaking it up with a fork, until browned, about 10 minutes.
Transfer the mixture to a slow cooker.
Add the salsa, broth, green pepper, chilies, and garlic and cook for three hours on high or for seven hours on low, then uncover and continue cooking for another hour.
Optionally, add 1 can of Rotel diced tomatoes and green chilies for a little bit of zip and/or some dried, ground peppers, ~ 1/2 tsp.
Add the tortilla chips and cook uncovered for 15 minutes more.
Stir in the cilantro, salt, and pepper and spoon into bowls, serve topped with sour cream if you’d like.