Thaw shrimp according to package directions.
Drain spinach well, pressing between paper towels, and set aside.
Saute onion in hot oil in a large skillet over medium-high heat 5 minutes or until tender. Stir in tomatoes, broth, and Greek seasoning; bring to a boil, and cook, stirring occasionally, 10 minutes.
Add shrimp; cook 2 minutes. Stir in spinach. Spoon over pasta; sprinkle with cheese, and serve immediately.