In a large pot, heat olive oil over medium heat. Add the diced onion and sauté until translucent, about 4-5 minutes.
Stir in the minced garlic and cook for an additional minute until fragrant.
Add the ground turkey or chicken to the pot. Cook until browned and fully cooked, breaking it apart with a spatula, about 6-7 minutes.
Mix in the taco seasoning, stirring to coat the meat evenly with the spices.
Pour in the chicken or vegetable broth, then add the rinsed black beans, kidney beans, diced tomatoes with green chilies, and corn. Stir to combine.
Bring the soup to a simmer, cover, and let cook for about 15-20 minutes, allowing the flavors to meld together.
Remove the pot from heat and stir in the Greek yogurt until fully incorporated, creating a creamy texture. If the soup is too thick, add additional broth to reach your desired consistency.
Taste and adjust seasoning with salt and pepper as needed.
Serve the soup hot, topped with shredded cheese, fresh cilantro, avocado slices, and lime wedges on the side.
Notes
For a spicier kick, add jalapeños or extra chili powder.