Cook ravioli in 4 cups boiling salted water 6 to 8 minutes or until tender; drain.
Meanwhile, in large skillet cook walnuts in hot oil over medium heat 2 to 3 minutes; remove with slotted spoon. Add zucchini and green onion. Cook and stir 2 to 3 minutes or until crisp-tender.
Add pasta, walnuts, milk, and 3/4 cup cheese to pan. Cook and toss 1 minute. Season with 1/8 teaspoon each salt and black pepper. Transfer to serving bowls; sprinkle with remaining cheese. Makes 4 servings.