Heat olive oil in a pot or large skillet over medium heat. Add chopped onion and cook until softened, about 3 to 4 minutes.
Add minced garlic and cook for 30 seconds until fragrant.
Stir in cooked chicken, white beans, ground cumin, chili powder, oregano, salt, and pepper.
Pour in chicken broth to reach desired chili consistency, about 1 to 2 cups. Mix well.
Bring to a gentle simmer and cook for 10 to 15 minutes to meld flavors and thicken.
Warm the corn tortillas in a dry skillet, grill, or oven wrapped in foil until soft and pliable.
Assemble tacos by spooning chili mixture onto each tortilla and adding preferred toppings like lettuce, tomatoes, avocado, cilantro, or sour cream.
Serve immediately with lime wedges for squeezing over the tacos.