In a medium bowl, whisk together the mayonnaise, crema or sour cream, Tajín, lime juice, milk, and sea salt until smooth. Set aside.
Season both sides of the chicken breasts with chili powder, cumin, paprika, garlic powder, oregano, salt, and black pepper.
Heat olive oil in a large skillet over medium heat.
Add the chicken and cook for 4–6 minutes per side, or until the internal temperature reaches 165°F (74°C).
Transfer the cooked chicken to a plate and allow it to rest for several minutes before slicing.
Using the same skillet, add a small amount of oil if necessary.
Add the corn, diced onion, and jalapeño.
Increase heat to high and cook for 4–5 minutes, stirring occasionally, until the corn becomes lightly charred and tender.
Remove from heat and stir in half of the prepared sauce to create a creamy street corn mixture.
To assemble the Street Corn Chicken Rice Bowls, divide cooked rice among serving bowls.
Top with sliced chicken and a generous scoop of the street corn mixture.
Garnish with avocado, cotija cheese, cilantro, and lime wedges.
Drizzle with additional sauce before serving if desired.