Preheat your oven to 350°F (175°C) and grease a large casserole dish.

Heat olive oil in a large pot over medium heat, add chicken breasts, and cook for about 6-7 minutes on each side until golden brown. Shred chicken after cooking.

Bring a large pot of salted water to boil, cook spaghetti until al dente, about 8-10 minutes, then drain and cool slightly.

In a mixing bowl, combine shredded chicken, spaghetti, cream of chicken soup, chopped bell peppers, paprika, cayenne pepper, garlic powder, and one cup of cheddar cheese. Mix well.

Transfer mixture to the casserole dish and sprinkle remaining cheddar cheese on top evenly.

Bake in the preheated oven for 25-30 minutes until bubbly and golden.

Remove from oven, let it rest for 5 minutes, and garnish with sliced green onions before serving.