In a large bowl, combine buttermilk and chicken. Cover and refrigerate for at least 30 minutes.
In another bowl, mix flour, paprika, garlic powder, onion powder, salt, and pepper. Remove chicken from buttermilk, coat well in the flour mixture.
Heat oil in a skillet over medium-high heat. Fry chicken for about 7-8 minutes per side until golden brown and cooked through. Drain on paper towels.
In a large pot, heat olive oil over medium heat. Add sliced onions and garlic; sauté until soft. Stir in collard greens and pour over the chicken broth. Season with red pepper flakes, salt, and pepper. Cover and simmer for about 45 minutes until greens are tender.
Preheat the oven to 400°F (200°C). In a mixing bowl, combine cornmeal, flour, sugar, baking powder, and salt.
In another bowl, whisk together buttermilk, melted butter, and eggs. Combine wet and dry ingredients, mix until just combined.
Pour batter into a greased baking dish and bake for 20-25 minutes or until golden and a toothpick inserted comes out clean.
Cook elbow macaroni according to package instructions. In a saucepan, melt butter over medium heat; whisk in flour and cook for 1 minute. Gradually add in milk, stirring until thickened.
Stir in cheese, mustard powder, garlic powder, salt, and pepper until melted and smooth. Combine with cooked macaroni.
On dinner plates, serve crispy fried chicken alongside collard greens, cornbread, and a generous scoop of macaroni and cheese.