Rinse rice until water runs clear. Combine with 1½ cups water and a pinch of salt in a saucepan. Bring to a boil, then reduce heat to low, cover, and simmer 15 minutes. Let stand covered 5 minutes.

Toss chicken with chili powder, cumin, garlic powder, and ½ tsp salt. Heat 1 tbsp oil in a skillet over medium-high heat, add chicken, and cook undisturbed 5 minutes until browned. Stir and cook 2-3 minutes more until cooked through. Transfer to a plate.

Add remaining 1 tbsp oil to the skillet and raise heat to high. Add corn and spread in one layer. Cook 2-3 minutes without stirring, then stir and cook 1-2 minutes until charred. Season with salt.

Stir together sour cream, chipotle, adobo sauce, lime juice, and a pinch of salt. Thin with water if needed.

Divide rice among bowls. Top with chicken, corn, avocado, cilantro, and cheese. Drizzle crema and serve with lime wedges.