MX goggles usually don't have anything to help fogging most motocross lenses are single pane and most ski goggles are double pane. mx goggles usually have a wider strap and nonslip stuff on the back of the strap for helmets
you can get all kinds of lenses for MX goggles and they work really well without fogging (snowmobile guys use mx gogs). just ask the shop what lenses they have.