Heat oil in large saucepan over medium heat.
Add white and pale green parts of green onions, 1 tablespoon cilantro and garlic
Sauté until tender, about 2 minutes.
Add curry paste; cook until fragrant, about 1 minute.
Add clam nectar, coconut milk, chiles, lime leaves and fish sauce
Bring to simmer.
Add carrot and cover and cook until carrot is just tender, about 5 minutes
Layer bok choy, shrimp, scallops, then clams in pan
Cover and simmer until clams open and seafood and bok choy are cooked (discard clams that do not open), about 5 minutes.
Stir in dark green parts of green onions, 2 tablespoons cilantro, and basil.
Divide rice among 4 shallow bowls. Ladle curry over rice and serve.