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