1. Prepare grill to medium-high heat.
2. Heat a medium nonstick skillet over medium heat. Coat pan with cooking spray. Add shallots and garlic to pan; cook 1 minute, stirring frequently. Add 1/4 cup chicken broth. Cover, reduce heat, and cook 3 minutes or until shallots are tender. Stir in remaining 1 1/4 cups broth, potatoes, and chorizo; bring to a simmer. Simmer 20 minutes or until potatoes are tender; stir in 1/4 teaspoon salt. Add spinach to pan; cover. Remove from heat; stir to combine. Keep warm.
3. Sprinkle remaining 1/2 teaspoon salt and paprika evenly over fillets. Lightly coat fillets with cooking spray; arrange fillets in a single layer, skin side up, on grill rack. Grill 2 minutes. Rotate fillets a quarter turn on the same side; grill 3 minutes or until well marked. Turn fillets over; grill 5 minutes or until desired degree of doneness.
4. Place 1 fillet in each of 4 shallow bowls; ladle 3/4 cup potato mixture over fish. Drizzle 3/4 teaspoon oil over each serving.