First Nicosia is about a 1.5 hour drive from Paphos. You may be able to book an excursion through your tour oprerator (assuming you are staying in a hotel or appartment) but if you want to explore the city at leisure I would recommend you go by car/taxi or bus. Options are:
Bus: There are 3 services a day to Nicosia leaving from the bus station or if you book in advance they may be able to pick up from your hotel (ask your hotel for details)
Taxi: Go for one of the "service" taxis which group individuals together rather than having to pay for a taxi yourself. These are low cost, around € 12-15 euros though prices may have changed in last few months due to fuel increases.You can book through your hotel or check with tourist information when you get here.
Car: Most flexible option though will cost a bit more but car hire is cheap in November as low season. It's not hard to park in Nicosia. Just get a copy of the city centre map and head for the walled section. There are car parks all around the ancient walls and then you are only a few minutes walk from the centre.
