Marinate the chicken: Whisk together 3 tablespoons lime juice, 1 ½ teaspoon Tajin seasoning,1 teaspoons garlic powder, and 1 pinch salt and pepper. Coat 2 pounds chicken breasts fully in the marinade and let sit for at least 30 minutes or up to 2 hours in the fridge.
Cook the rice: Cook 1 ½ cups white rice according to package instructions. Fluff with a fork and keep warm.
Grill the chicken: Heat a grill or grill pan over medium-high heat. Cook the marinated chicken for 6–14 minutes per side until it reaches an internal temperature of 165°F. Rest for 5 minutes, then slice into bite-sized pieces.
Cook the corn: Cut the kernals off the cob. Then cook over medium-high heat, turning occasionally, until charred on all sides. Let cool slightly.
Make the elote topping: In a bowl, combine the corn kernels, 3 tablespoons mayonnaise or greek yogurt, 1 tablespoons lime juice (for elote topping), ½ cups cotija cheese, crumbled, ⅓ cups fresh cilantro, chopped, and ½ teaspoon chili powder (for elote topping). Stir until the corn is well coated. Taste and adjust seasoning as needed.
Assemble the bowls: Divide the rice between bowls. Top with sliced chicken and a generous scoop of the elote mixture. Add 2 avocado, sliced and garnish with extra cilantro and 2 lime wedges, for serving on the side. Squeeze lime over everything before eating.
