Bring 6 cups water and 1 Tbsp. Greek seasoning to a boil in a Dutch oven over high heat; add green beans. Cook 6 minutes or until beans are crisp-tender; remove beans, draining well. Wipe Dutch oven dry with paper towels.
Melt butter in Dutch oven over medium heat. Add green beans and 1/2 tsp. Greek seasoning, tossing to coat; cook, stirring constantly, 2 minutes or until thoroughly heated.