The short answer is yes, it's safe to feed your cat cashews. The longer answer: You should only feed them cashews infrequently, in tiny amounts, and without any seasonings.
Cashews do provide a range of health benefits. They contain healthy fats that help promote good cardiovascular health and improve brain function. They also have antioxidants that fight free radicals in the body, which helps reduce inflammation and prevent chronic diseases such as cancer.
But remember that too much of anything can be harmful. While cashews themselves aren't toxic to cats, eating too many over time can lead to weight gain or even obesity. (Healthy fats are still fats!) Also, keep in mind that some cats may have allergies or sensitivities, so pay attention if you see any negative reactions like vomiting or diarrhea.
Cashews also have a hard outer shell that can cause digestive problems, so make sure the nuts are completely removed from their shell.
Finally, make sure the nuts are unseasoned and plain, as anything else could upset your cat's stomach. And don't mix the cashews with other nuts, since some other nuts are less safe to feed your cat.
Keep in mind that cats are obligate carnivores, which means they need to get most of their nutrients from meat-based protein. Nuts like cashews — or really any plant-based foods — should never displace the meat in your cat's diet.
As always, before introducing a new food item into your pet's diet, consult with your veterinarian first. If your cat eats cashews (or any food) and is showing signs of illness such as lethargy, diarrhea, or vomiting, reach out to your veterinarian immediately. If they require veterinary care related to eating any unsafe foods, pet insurance can help cover the cost of treatment.