You can walk to Het Nutshuis from Den Haag Centraal Station and the centre of The Hague. On leaving Den Haag Centraal Station, walk towards Malieveld to Herengracht. Cross over to Korte Poten. Walk across Plein to Binnenhof. Then cross over to Buitenhof and keep left of the Grote Kerk on to Gravenstraat, which becomes Riviervismarkt.
Tram line 16: get off at Gravenstraat.
Bus line 24: get off at Kneuterdijk.
You can get to Het Nutshuis by car quite easily. Navigate to Riviervismarkt 5, The Hague. You can stop and drop people off through the side entrance on Jan Hendrikstraat.
You must pay for parking around Het Nutshuis, either on the street or in a car park. The closest car park is Q-Park City Parking next to Hotel Ibis and the Esso filling station: just off Laan 8, 2512 GM.