Heat the large heavy-bottomed pot over medium heat and add diced onions and bell peppers. Cook, stirring occasionally, until they soften and become fragrant, about 5 minutes.
Add the ground beef or turkey to the pot, breaking it apart with your spoon. Cook until browned and no pink remains, about 8 minutes.
Stir in the diced tomatoes, corn, beans, and taco seasoning, ensuring everything is evenly coated and combined.
Pour in the broth or water, bringing the mixture to a gentle simmer. Reduce heat to low and let it simmer uncovered for about 20 minutes, stirring occasionally.
Taste the soup and adjust seasoning if needed—maybe a pinch more chili powder, salt, or pepper to deepen the flavor.
Once the flavors have melded and the soup has thickened slightly, ladle it into bowls and serve hot, topped with your favorite garnishes like cheese, sour cream, or cilantro.