Wash rice in a large bowl under cold water for 2-5 minutes until the water runs clear. Soak for at least 5 minutes. Boil 3.5 cups of water in a large saucepan, pour rice and let simmer on low heat for 10 minutes or until the water has dried into the rice and the rice is soft. Place 2 tablespoons of butter on the rice to melt with the heat off, Cover and set aside.The cilantro and lime will be added later before serving.
In a medium bowl Mix the halved chicken breast with the olive oil, tomato paste, taco spice mix. Squeeze half of a lime into the mixture and mix. Cover the chicken and allow to marinate in the fridge for anywhere from 15 minutes-3 days.
Heat a grill, griddle or pan over medium-high heat, place chicken on grilled and cook for 5 minutes on each side. remove from heat and set aside.
While the chicken is on the grill, chop all of the veggies and salad.
After the chicken has finished cooking and the rice is ready, In a medium bowl toss the rice with minced cilantro, salt and the juice of half a lime. Spoon the rice into bowls, top with salad mixture (beans, corn, bell peppers, tomatoes, onions, cilantro). Place chicken on top and top with 1 teaspoon of sour cream and chopped scallions.
Enjoy cold or warm!