According to Via Michelin, the driving time between Tomar and Coimbra is in the order of 1hr30 to 1hr50 depending on the route. As regards touring the Nazare, Fatima, Tomar area in two days, this is difficult to assess as I do not know your tastes.
Bearing in mind that there are also famous centres such as Batalha, and Alcobaça in the area, you may be a bit pushed.
