Wash the chestnut pumpkin thoroughly, peel it, and cut into bite-sized pieces.
Place the chestnut pumpkin in a steamer and steam for 15 minutes.
Transfer the steamed chestnut pumpkin to a bowl and let it cool.
Wash the iceberg lettuce and cherry tomatoes, then cut into bite-sized pieces.
Add the chestnut pumpkin, iceberg lettuce, and cherry tomatoes to the bowl and mix well.
Add olive oil, salt, and pepper, then toss gently.