Heat olive oil in a large skillet or pot over medium heat. Add chopped onion and cook until softened, about 3 to 4 minutes.
Stir in minced garlic and cook for 30 seconds until fragrant.
Add cooked chicken, white beans, ground cumin, chili powder, oregano, salt, and pepper.
Pour in chicken broth to create a soupy mixture, using 1 to 2 cups depending on desired thickness, and stir to combine.
Bring mixture to a gentle simmer and cook for 10 to 15 minutes to meld flavors and thicken slightly.
Warm corn tortillas in a dry skillet, on the grill, or wrapped in foil in the oven until soft and pliable.
Assemble tacos by spooning the white chicken chili mixture onto each warm tortilla and adding desired toppings.
Serve immediately with lime wedges on the side for squeezing over the tacos.