To prepare the tomato basil sauce, heat olive oil in a medium saucepan over medium heat. Add onion and garlic, and sauté until translucent. Add crushed tomatoes and chicken stock, and bring to a boil. Reduce the heat, and simmer for 20 minutes. Add cream, and return to a boil. Simmer for 5 minutes. Stir in basil. Set aside.
To prepare the catfish, mix cashews, garlic powder, cayenne pepper, basil and black pepper in a shallow dish or on a piece of wax paper.
Mix eggs and milk in another shallow dish. Dip catfish fillets in the egg mixture; then dredge in the cashew mixture. Set aside on a wax paper-lined baking sheet.
Pour a ½ inch of oil into a large skillet, and heat over medium heat. Place the fillets in the hot oil, and fry for 5 or 6 minutes on each side or until fish flakes easily when tested with a fork.
Spoon tomato basil sauce onto each serving plate, and top with a catfish fillet.