Season the chicken. Toss the 1-inch chicken pieces with 1 tbsp olive oil, 1 tsp chili powder, ½ tsp cumin, ½ tsp garlic powder, ½ tsp paprika, salt, and pepper until evenly coated. This step can be done the night before — refrigerate covered and the seasoning penetrates deeper, saving time on prep day.
Cook the chicken. Heat a large skillet over medium-high heat. Add the seasoned chicken in a single layer. Cook 5–6 minutes, flipping once halfway through, until the internal temperature reaches 165°F (74°C) and the edges are golden. Remove from the skillet and rest 5 minutes before portioning.
Char the corn. In the same skillet, add the remaining 1 tbsp olive oil over high heat. Add the 2 cups of corn kernels and cook without stirring for 2–3 minutes until charred spots develop. Stir once and cook another 2 minutes. Remove from heat. Charred corn keeps well in a separate airtight container for up to 5 days.
Build the street corn mixture. In a medium bowl, combine the charred corn, 2 tbsp mayonnaise, ¼ cup crumbled cotija, 1 tbsp fresh lime juice, ½ tsp chili powder, and 2 tbsp of the chopped cilantro. Stir until the corn is fully coated. This mixture can be made ahead and refrigerated in an airtight container for up to 4 days.
Assemble the bowls. Divide the 2 cups of cooked rice evenly among 4 meal prep containers — ½ cup per bowl. Add the portioned chicken pieces and ¼ cup of rinsed black beans per bowl. Top each with an equal portion of the street corn mixture.
Finish and store. Seal containers and refrigerate. Do not add avocado during batch assembly — slice fresh at each serving and add alongside a pinch of the remaining cilantro as garnish. Bowls keep 5 days in the fridge. The chicken, rice, beans, and street corn mixture can also be frozen separately in airtight containers for up to 2 months. Reheat the base components in the microwave for 2–3 minutes, then top with fresh avocado and cilantro before eating.