Reserve one seasoning packet from the ramen packages and discard the other packet(s).
In a large saucepan, bring 2 quarts of water to a boil. Break the ramen noodles slightly and add them with the cut-up vegetables.
Return to a boil, then reduce heat and simmer gently, uncovered, for 3 minutes. Drain the noodles and vegetables in a colander and return them to the saucepan.
Meanwhile, make the sauce: in a medium saucepan whisk together 1ΒΌ cups water (or coconut milk), peanut butter, soy sauce, brown sugar, cornstarch, crushed red pepper, and the reserved seasoning packet until smooth.
Cook the sauce over medium heat, stirring, until it thickens and becomes bubbly; continue cooking and stirring for 2 more minutes.
Stir the chopped cooked chicken, drained water chestnuts, and drained bamboo shoots into the sauce and heat through.
Pour the chicken mixture into the saucepan with the noodles and vegetables and toss to combine evenly.
Transfer to a serving dish and top with chopped peanuts and sliced green onions before serving.
