Heat masala paste in a large, deep skillet over medium heat for a couple minutes, stirring occasionally. Add sour cream and chicken chunks to the skillet, stir to combine, then sauté until the chicken is mostly cooked through. Next, stir in the coconut milk and tomato puree to the skillet with the chicken then simmer for 15-20 minutes, or until sauce has thickened up to your liking. Serve over cooked white rice with chopped cilantro as garnish! Enjoy :)