Marinate the chicken: In a mixing bowl, combine lime juice, salt, pepper, garlic powder, paprika, and cumin. Add chicken breast and coat well. Let marinate for 30 minutes at room temperature.

Cook the chicken: Heat a grill pan or skillet over medium-high heat. Add marinated chicken and cook for 6-7 minutes per side until golden brown with char marks and internal temperature reaches 165°F. Remove and let rest for 5 minutes before slicing.

Prepare the rice: Rinse uncooked rice under cold water. In a medium saucepan, combine rice, 2 cups water, and 1/2 teaspoon salt. Bring to a boil, then reduce heat to low, cover, and simmer for 18-20 minutes (white rice) or 35-40 minutes (brown rice). Remove from heat and fluff with a fork.

Char the corn: If using fresh corn, steam for 5 minutes and cut kernels off the cob. Heat butter or oil in a large skillet over medium heat. Add corn, salt, and pepper. Sauté for 5-6 minutes, stirring occasionally, until corn develops charred spots.

Assemble the bowls: Divide fluffy rice among 4 bowls. Top with sliced grilled chicken and sautéed corn. Sprinkle with fresh cilantro, arrange avocado slices around the edges, and finish with a generous squeeze of fresh lime juice.