Begin by marinating the chicken. In a bowl, combine the buttermilk and chicken pieces. Cover and refrigerate for at least 30 minutes.
In a separate bowl, mix together the flour, paprika, garlic powder, onion powder, salt, and pepper. Remove the chicken from the buttermilk, letting excess drip off, then dredge in the flour mixture.
Heat oil in a skillet over medium heat. Fry the chicken pieces until golden brown and cooked through, about 10-12 minutes per side. Drain on paper towels.
While the chicken is frying, cook the macaroni. In a large pot, bring water to a boil and cook the macaroni according to package instructions. Drain and set aside.
In the same pot, melt butter over medium heat. Stir in the flour and cook for 1 minute. Slowly add milk while whisking to prevent lumps. Cook until thickened. Stir in cheese until melted, add mustard, salt, and pepper. Combine the macaroni with the cheese sauce.
For the collard greens, in a pot, heat olive oil over medium heat. Sauté the onion and garlic until soft. Add the chopped collard greens and chicken broth. Simmer for about 30 minutes until greens are tender. Season with salt and pepper.
Preheat the oven to 400°F (200°C) for the cornbread. In a bowl, combine cornmeal, flour, sugar, baking powder, and salt. In another bowl, mix milk, oil, and egg. Combine wet and dry ingredients, stirring until just mixed. Pour into a greased 9x13 baking dish and bake for 20-25 minutes until golden.
Once everything is ready, serve the fried chicken alongside macaroni and cheese, collard greens, and slices of cornbread.