Scrub the sweet potatoes and pat them dry with paper towels. Pierce each sweet potato several times with a fork.

Rub the sweet potatoes with 1 teaspoon olive oil. Sprinkle with ¼ teaspoon salt and ¼ teaspoon black pepper.

Place the sweet potatoes on the prepared baking sheet. Bake for 45 to 55 minutes, or until a fork slides easily into the center.

While the sweet potatoes bake, heat a large skillet over medium heat. Add the bacon and cook for 6 to 8 minutes, turning occasionally, until crispy.

Transfer the bacon to a paper towel-lined plate. Chop into small pieces.

In a large mixing bowl, stir together ½ cup Greek yogurt, light mayonnaise, 1 teaspoon parsley, ½ teaspoon dill, ½ teaspoon garlic powder, ½ teaspoon onion powder, ¼ teaspoon black pepper, and ¼ teaspoon salt until smooth.

Add the shredded chicken and half of the chopped bacon. Stir until evenly coated.

In a small bowl, mix ⅓ cup Greek yogurt, milk, ¼ teaspoon parsley, ¼ teaspoon dill, ¼ teaspoon garlic powder, ⅛ teaspoon onion powder, ⅛ teaspoon salt, and ⅛ teaspoon black pepper until smooth.

Remove the baked sweet potatoes from the oven. Cut a slit lengthwise across the top of each potato and gently press the ends toward the center to open.

Divide the chicken mixture evenly among the four sweet potatoes. Sprinkle the shredded cheddar cheese over the filling.

Return the stuffed sweet potatoes to the oven for 5 to 7 minutes, until the filling is heated through and the cheese melts.

Drizzle the Greek yogurt ranch over each stuffed sweet potato. Top with the remaining chopped bacon and sliced green onions.