Cook the spaghetti according to package instructions. Drain and set aside.
In a large bowl, toss the shredded chicken with the BBQ sauce.
Heat olive oil in a skillet and briefly sauté the chicken mixture to warm it up.
Stir in sour cream and adjust seasoning with salt and pepper.
Add the cooked spaghetti into the pan and toss everything together gently.
Transfer the mixture into a baking dish.
Top evenly with shredded cheese and bacon bits.
Bake at 350°F for 15-20 minutes until the cheese is melted and bubbly.
Sprinkle with sliced green onions just before serving.