In a 6-quart saucepan, combine pumpkin puree, chicken broth, and pear nectar. Bring to a boil over high heat. Cover, reduce heat to low, and simmer 10 minutes.
In a blender or the bowl of a food processor fitted with chopping blade, process 1 cup pumpkin mixture with peanut butter until smooth. Return to saucepan with the remaining pumpkin mixture. Add garlic, ginger root, green onion, lime juice, salt, and cayenne pepper; cook 10 minutes over medium heat.
Divide soup among soup plates and garnish with pumpkin seeds and chives, if desired. Serve immediately.