Cut the chicken breasts into bite-sized pieces and place them in a medium bowl.
Add the olive oil, paprika, cumin, chili pepper, 1/2 tsp kosher salt, and 1/2 tsp black pepper to the chicken; toss until evenly coated.
Heat a nonstick skillet over medium heat and cook the seasoned chicken until cooked through, about 7–8 minutes per side depending on thickness; transfer to a plate and set aside.
Cook the white rice according to package instructions, then fluff and keep warm.
Make the salsa: in a bowl combine chopped tomato, chopped onion, cilantro, white vinegar, lime juice, and 1/8 tsp kosher salt; mix until combined.
Divide chopped romaine, cooked rice, corn, black beans, and cooked chicken evenly among four bowls.
Top each bowl with sliced avocado, a spoonful of the salsa, sour cream, and shredded cheddar cheese.
Garnish with extra cilantro if desired and serve immediately.