Begin by placing the chicken thighs, salsa verde, green chiles, chopped garlic, jalapeño, garlic powder, onion powder, and cumin into a 6- to 8-quart slow cooker. Stir the ingredients together until they are evenly combined. Avoid adding salt at this stage, as jarred salsa often contains a high sodium content. Set the slow cooker to cook on low for 5 to 6 hours, until the chicken is tender and the flavors meld together. If you need to cook for a longer period, reduce the cook time to 4 hours and allow the slow cooker to switch to "warm" for the remainder of the time.