Grilled Shrimp Pesto Pizza

1 (16 oz.) Italian bread shell or prepared 12-inch pizza crust

1/3 cup prepared pesto sauce

2 cups (8 oz.) Sargento® Shredded 6 Cheese Italian, divided

8 oz. cooked shrimp, shelled and deveined

1/2 cup coarsely chopped softened sun-dried tomatoes

1/4 cup minced green onions

1/4 tsp. crushed red pepper flakes