Slice the chicken breasts or thighs thinly, about 1/2 inch thick, to ensure quick and even cooking. Toss the chicken pieces in a bowl with the olive oil, chili powder, cumin, salt, and pepper. Make sure every piece is evenly coated in the seasoning.

Heat a large skillet or grill pan over medium-high heat. Add the seasoned chicken and cook for 4 to 6 minutes per side, depending on thickness, until the chicken is browned, thoroughly cooked, and juicy with an internal temperature of 165°F. Remove from the pan and dice into bite-sized pieces; set aside and keep warm.

Using the residual oil and heat in the same skillet (or add a teaspoon of fresh oil if needed), add the corn kernels. Cook over medium-high heat, stirring occasionally, for about 5 to 8 minutes, aiming for a beautiful, golden-brown char on some kernels. This char is essential for smoky flavor.

While the corn is charring, whisk together the mayonnaise (or Greek yogurt), sour cream, lime juice, garlic powder, and cayenne pepper in a medium bowl. Taste and adjust seasoning; add a splash of milk or water if too thick, or more lime juice if needed.

Remove the charred corn from the heat and stir it immediately into the creamy dressing. Add the chopped cilantro, crumbled cotija cheese, and diced jalapeño (if using). Stir gently until combined.

Start with a generous base of warm rice in each bowl. Add a portion of the seasoned diced chicken over the rice. Spoon a hearty serving of the creamy street corn mixture over the top. Garnish with extra cilantro, a sprinkle of chili powder or Tajín, and a fresh lime wedge. Serve immediately.