This is still our go-to place for groceries even though we own a Costco membership for years. We've compared prices from meats to produce to basic household items and the commissary prices are very competitive (not to mention tax-free). The produce aisle are always full with fresh vegetables, which may not always be the case in other commissaries, so Nellis definitely ranks high in my list (other top-quality commissaries include NAS San Diego and Travis AFB). However, we still go to Costco for fruits as they usually have better berries, apples, and grapes.
Their "international" aisle is limited but occasionally I would find good finds, such as on New Year's eve, I was ecstatic to score a gelatinous rice flour mix so we can make "palitaw" (traditional Filipino food that should be cooked when the clock strikes midnight).
The cashiers and baggers are helpful and warm. I also just want to reiterate that the baggers in all commissaries ONLY work for tips as they are not salaried employees, so please make sure you give them a few bucks when they help you take your groceries to your car.