Cook the rice according to package directions and keep it warm. Fluff with a fork just before assembling.

Heat a grill or grill pan to medium-high. Season chicken breasts with salt and pepper. Grill until the internal temperature reaches 165°F (about 6 to 8 minutes per side depending on thickness). Let the chicken rest for 5 minutes, then slice against the grain.

While the chicken rests, heat a skillet over medium heat and add the olive oil. Add the corn and cook, stirring occasionally, until the kernels are lightly charred, about 3 to 4 minutes.

Sprinkle the chili powder, smoked paprika, cumin, salt, and black pepper over the corn. Toss and cook another 30 seconds so the spices bloom.

Make the lime crema by whisking the sour cream or Greek yogurt with lime juice, garlic powder, and 1/4 teaspoon salt. If the crema is too thick, add a teaspoon of water at a time until it reaches a pourable consistency.

Assemble bowls: divide the rice between bowls, top with sliced chicken, charred corn, black beans, tomatoes, red onion, and crumbled cotija.

Drizzle lime crema over each bowl and garnish with chopped cilantro. Serve immediately.