Dice the chicken into small pieces. Combine taco seasoning in a small bowl and set aside.
To make the pico de gallo, set 3 tablespoons of the diced onion aside and place it in a bowl with tomato, cilantro, 2 teaspoons lime juice, and 1/4 teaspoon salt. Set aside.
Add olive oil to a large skillet over medium-high heat. When hot, add the chicken and cook until it starts to brown, about 2 to 3 minutes.
Add the remaining onion, poblano pepper, and taco seasoning to the skillet and cook until it softens, about 2 to 3 minutes.
Add 1/2 cup water and corn. Cook for 1 to 2 minutes, then remove from heat.
Divide rice into 4 bowls, top with chicken, cheese, pico de gallo, and optional sour cream.
