Put chicken breasts into a pot and cover with water. Heat to a simmer and cook for about 10-15 minutes until chicken is cooked through. Remove chicken from the water and set aside to lightly cool then shred the chicken with two forks. Set aside.

Meanwhile, heat oil in a large pot over medium heat, add the onion, garlic, and some salt and pepper. Cook for about 5-6 minutes until vegetables have softened somewhat.

Stir in tomato paste and cook for about 2 minutes.

Stir in diced tomatoes, shredded chicken, and broth. Bring to a simmer, reduce the heat, and cover. Simmer 15-20 minutes.

Spoon some broth out of the pot and place into a bowl. Stir in greek yogurt. Once greek yogurt has been fully incorporated with the broth, return the mixture to the pot and stir.

Stir in chopped kale and tortellini. Simmer for time listed on tortellini package. Season with salt and pepper to taste and serve.