Saute onion and garlic until fragrant.
Add the shredded carrot and saute for a couple minutes longer.
Season to taste.
Chop walnuts coarsely.
Mix sauce ingredients together and pour two-thirds over the onion and garlic mixture and heat through
Add the chickpeas and nuts to the pan and stir into the onions
Season to taste.
Roughly chop the water chestnuts and add to the mixture.
In a separate pan, heat the remaining sauce through to serve on the side.
Serve with the wedges of romaine lettuce.