a lot of historical place and nature place. i can't say it by word. come and feel it! you will not disappointed
Day trips to nearby wadis, forts, tombs, etc. make Nizwa worthwhile visiting. We missed the fort in town due to maintenance.
The bee-hive tombs are a must. Buy an off-roading book for Oman; otherwise, most sights will be hard to find. Also buy a map and bring your GPS with coordinates already in hand for the sights you want to see.
The town itself has become a tourist trap with newly built reproduction of an Arab souq and fort. The surrounding area is rugged and required either a 4WD vehicle or willingness to hike many hours on VERY rough terrain.
Stay minimum 2 days in nizwa. Check Al hoota cave availability. Nizwa for is only till 11.00am on friday.
I didn't get to see all of Nizwa, but I did get to see the fort and mosque in the center of town as well as the souk that is right in the middle of all that.
It's well worth stopping by to explore. Great sights and great food in the area as well.