Heat coconut oil in a wok or large deep skillet over medium heat.
Add the onion, garlic, carrots, mushrooms, and pork. Season lightly with salt and pepper. Cook, stirring occasionally, for 4-5 minutes until the vegetables soften and the pork browns.
Add water chestnuts and continue cooking for 2-3 minutes until the pork is cooked.
Reduce heat to medium-low and add soy sauce, oyster sauce, sesame oil, and rice vinegar. Cook, stirring occasionally, for 6-7 minutes until the sauce thickens.
Spoon the pork mixture into lettuce wraps and top with sliced scallions and roasted cashews. Serve with a lime wedge and enjoy!