Yes, we recommed you the ”Chuo Taxi Airport Direct”. Please refer this page for the details of their service (from Haneda airport, it will be a shared van service, and from Narita airport, it will be a private charter). We are happy to arrange this service for you. Please let us know your flight information, number of passengers and the number of luggage to book this service.
Another option will be the “Nagano Snow Shuttle”. If the time meets well with your flight schedule, this will be a great option for you. Please refer to this page for the details of their service.
Otherwise, how about renting a car at the airport and driving to Hakuba? In that case, please make sure you book a 4WD car with snow tires.