Slice each zucchini in half lengthwise and scoop out the flesh to create a boat-like cavity.
Brush the interior of each zucchini half with olive oil and season with salt and pepper. Bake cut side down for 10-12 minutes.
In a large mixing bowl, combine shredded chicken, buffalo sauce, softened cream cheese, ½ cup of cheddar cheese, and chopped green onions. Mix until creamy.
Flip the zucchinis over and fill each with the buffalo chicken mixture.
Sprinkle the remaining ½ cup of cheddar cheese on top and add blue cheese crumbles if desired.
Return to the oven and bake for an additional 15-20 minutes until cheese is melted and bubbly.
Remove from the oven and let cool for a few minutes. Garnish with additional chopped green onions before serving.