Nagano worth a trip if already staying in Matsumoto?

Spending a night in Matsumoto in the first week of December. Was wondering if it's worth going to Nagano and also staying there for a night as well (instead of going back to Tokyo). Plan currently is to just check Matsumoto out and also see the Kiso area.

Haven't been to Nagano before so I'm not sure if it's worth a full extra day! If I don't go to Nagano then I would use that time going to somewhere like Nikko later in the trip.

by FedoraTippinGood