Add oil and sautee chicken (or use pre-baked or pan grilled chicken).

Add onion, beans, diced tomatoes, bell pepper, and beef stock.

In an Instant Pot: Cook 5 minutes in an instant pot on soup setting/medium pressure with a forced release

On the Stovetop: bring to a boil in a large pan on the stovetop and reduce heat to a soft rolling roil for 5 minutes

In a slow cooker: cook on high for 1 hour, cook on medium for 2 hours, then keep warm.

Plate immediately and top with tortilla strips, as well as optional cheese and cilantro garnish (a little avocado or sour cream also is quite nice on top.)