Preheat a large skillet to medium heat with butter, ghee or tallow.

Add diced onions and salt, and sauté until translucent.

Add diced bell peppers and sauté for about 2 minutes, until slightly softened.

Add minced garlic and sauté until fragrant (about 30 seconds), stirring constantly. Take it off the heat immediately once fragrant, or the garlic may overcook and become bitter.

Add sauteed veggies to slow cooker or large pot, along with strained or diced tomatoes, spices, yogurt, and, taco seasoning mix,  lime juice. Stir until well combined.

Add chicken breasts and combine with other ingredients.

Set slow cooker to high, and cook for 3 hours, or until chicken falls apart easily.

If using a large pot. Set stove to medium high heat and bring to a low boil. Once boiling, reduce heat to medium low and simmer for about 3 hours, stirring occasionally to ensure the bottom does not burn.

After about 3 hours, shred chicken with two forks by pulling apart on each side, until all chicken is shredded. Combine well with the sauce it was cooked in.

While still hot, add shredded cheese and cilantro. The cheese will melt into the thick sauce.