In a mixing bowl, combine lime juice, avocado oil, chili powder, ground cumin, garlic powder or minced garlic, salt, and black pepper to create the marinade.
Add chicken thighs to the marinade and toss to coat evenly. Cover and refrigerate for 15 to 30 minutes to infuse flavors.
Heat a skillet over medium-high heat and add oil if needed. Sear chicken thighs for 8 to 10 minutes per side until cooked through and browned.
Remove chicken from skillet and let rest for 5 to 10 minutes before slicing into strips.
Prepare the street corn topping by mixing sweet corn kernels, red onion, half of the sour cream, mayonnaise, Cotija cheese, and chili powder in a bowl.
Season the corn mixture with salt, pepper, and lime juice to taste and stir to combine well.
Heat prepared rice in a microwave-safe bowl or saucepan with a splash of water until warm and fluffy; fluff with a fork before serving.
Assemble the bowl by dividing warmed rice among plates, topping with sliced chicken and a scoop of the street corn mixture.
Garnish each bowl with extra Cotija cheese, fresh cilantro leaves, lime wedges, and a drizzle of reserved sour cream if desired.
Optionally, add a sprinkle of Tajín or chili powder and an extra squeeze of lime for added flavor before serving.